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THE 



BY 

JUSTUS VON LIEBIG 



EDITED BY 



JOHN BLYTH, M.D« 

PKOFESSOE OF CnElIISTKT IIT QUEEN'S COLLEGE, COEK 



LONDON 

WALTON & MABERLY 

UPPEE GOWER STREET, and IVY LANE, PATERNOSTER ROW 

1863 



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LONDON 
PBIKTED BT SPOTTISWOODE AND CO, 

NEW-SIEBEI SQUAEE 



EDITOR'S PREFACE. 



IIST the following work Baron Liebig has given to tlie 
public his mature views on agriculture, after sixteen 
years of experiments and reflection. The fundamental 
basis of the work is still the so-called Mineral Theory, 
which holds that the food of plants is of inorganic 
nature, and that every one of the elements of food 
must be present in a soil for the proper growth of a 
plant. The discovery of the remarkable power of ab- 
sorption possessed by arable soils has necessarily led to 
a modification of the views regarding the mode in which 
plants take up their food from the soil. As the food of 
plants cannot exist for any length of time in solution in 
soils, it is clear that there cannot be a circulation of 
such solution towards the roots, but the latter must go 
in search of food. Hence the great importance of 
studying the ramification of the roots of plants, and 
the mode of growth of the different classes of plants 
cultivated by man. The first chapter is devoted to the 
consideration of the growth of plants, of the formation 
of their roots, and of their power of selecting food, 
and the part played by the mineral matters which are 
absorbed. 

If the food of plants is not in solution in the ground, 

A 2 



IV EDITORS PEEFACE. 

• 

we can conceive that those portions of the soil traversed 
by the numerous root ramifications will be more or less 
exhausted of food elements, whilst the immediate neigh- 
bouring portions are still rich in them. If, therefore, a 
succeeding crop is to grow equally well on all parts 
of a field, there must be a thorough mixing of the 
exhausted and of the unexhausted portions of soil. This 
is effected by mechanical means, by manures, or by 
certain chemical compounds. Hence the necessity of 
becoming acquainted with the nature and properties of 
the soil and subsoil. The second chapter is devoted to 
this subject. 

The soil consists of arable surface soil and subsoil. 
In the former is accumulated the nutriment of plants 
chiefly cultivated for the food of man. This accumula- 
tion is effected by the absorptive power of the arable 
soil for mineral matters, by which soluble salts are 
removed from solution, and even chemical decompo- 
sition of the most stable compounds is brought about, 
and the bases or acids are retained by the soil in a firm 
state of combination. It is the presence of food in the 
soil in this state of physical combination which is alone 
available for the nutrition of plants. On the abundant 
or scanty supply of food in this state depends the fertility 
or sterility of a soil. In fertile soils food is present 
also in another form, in which it is not immediately 
available for the nutrition of plants. It exists as 
chemical compounds which are not soluble in Avater, 
or acids until rendered so by the action of powerful 
chemical agents, or to a mucli smaller extent by the 



EDITORS PREFACE. V 

slower process of the decomposing action of tlie weather. 
Wlien the food is ehminated by disintegration (by fallow 
and mechanical operations) from this inert state of 
chemical combination, it passes into that of physical 
combination with the earthy particles before it is ab- 
sorbed by the plant. Each kind of soil has its o^vn 
absorptive power for causing the food to pass into a 
state of physical combination. Wlien manure is applied, 
its greater or less dispersion throughout the soil will 
depend on this power. In general it is absorbed and 
fixed by the upper few inches of the soil, a smaller 
quantity penetrates to the lower layers, and scarcely 
any at all to the deep layers and subsoil. Hence when 
a subsoil is exhausted, manure cannot restore its fertility. 
From this pecuhar property of soils of arresting the 
cu-culation of solutions of the food of plants, arises the 
necessity of employing means for the distribution of 
food, and for the uniform mixture of the different layers 
of the soil! The manner in which this is effected by 
mechanical operations, by organic matter, by manures, 
by certain chemical salts, &c., is pointed out in chapters 
second, third, and twelfth. 

The quantity of food in a state of physical combina- 
tion in any fertile soil is only limited. Continuous 
cultivation without replacement of all the mineral matters 
removed in the crops destroys fertility, either by causing 
tlie absolute loss of the assimilable food, or by altering 
the proper relative proportions between the different 
elements of food, to such an extent that the due growth 
of all parts of the plant is altered. For the successful 



VI EDITOES PKEFACE. 

growth of a plant in all its parts, every element of food- 
is required. Not one substance has any superior fertilis- 
ing power over another. The average crop of an un- 
manured field is always regulated by that element of 
food which is present in minimum quantity. The effect 
of a manure when beneficial is merely to increase the 
relative proportion of this minimum element. If the 
mi?iimiim matter was known in each case, its direct 
application would be sufficient to increase the fertihty 
of the soil. But as in general this point is not ascer- 
tained, the application of farm-yard manure is certain 
in producing a fertilising eflect, simply because it is a 
complex mixture containing all the food elements of 
plants, and consequently whilst supplying other matters 
which are not iminediately wanted, it also furnishes the 
minimum substance. In chapter fourth, is discussed 
the question of this altered composition of the ground 
by cultivation. 

In chapter eleventh, the fact that not one of the 
elements of food by itself possesses any superior nutri- 
tive value over the others is further discussed. Nitro- 
genous food, like aU the rest, must be present if a plant 
is to grow properly, but no excess of this element of 
food will of itself produce more abundant crops. The 
analyses of soils show that they abound in nitrogen. 
Were all other sources of this element wanting^ 
there would still be a continued supply provided for 
in rain and dew, and in the many processes of oxida- 
tion going on at the surface of the earth. Probably, 
wherever we have a generation and circulation of car- 



EDITORS PEEFACE. VU 

boniG acid, there is also a provision for the formation of 
nitrogenous compounds. When Nature thus provides 
for a supply of nitrogen without the aid of man, it is 
likely that exhaustion of all other elements of food in 
the soil will take place by cultivation before this occurs 
with nitrogen. The inefficacy of the mass of nitrogen 
in the soil cannot be attributed to its existing in two 
forms, in one only of which it is assimilable. This is 
proved by experiments with soils and with farm-yard 
manure. When the nitrogen of the soil is not available, 
some other cause must be sought for than its existence 
in a state in which it is sparingly assimilable. This 
cause will be found to be the absence of some other 
elements of food, which, upon being supplied, will at 
once render the seemingly inoperative nitrogen at once 
energetic. 

The diminution of the amount of available food 
elements in the arable surface soil, by the cultivation 
and sale of corn, necessitates the restoration of the 
removed mineral matters. This is effected to a limited 
extent by foreign manuring agents, but chiefly by the 
formation of manure by means of fodder plants. By 
the system of rotation, green crops which draw their 
nutriment from the subsoil are introduced between the 
cereals. By the deep penetrating roots of the former, 
the mineral matters of the subsoil are absorbed, and 
in the form of manure are transferred to the arable 
surface soil. But if this process continues, and the corn 
and cattle are still sold, and no replacement from without 
is made of the lost mineral matters, the time will arrive, 



Vlll EDITORS PREFACE. 

sooner or later, when tlie subsoil becomes exhausted, 
and the surface soil having no longer a reservoir from 
which to draw supplies by means of fodder plants, is 
also unable to bear remunerative crops. This natural 
progress of the system of farm-yard manuring is fully 
discussed in chapter fifth. The reader must not suppose 
that the condemnation passed on the system of farm-yard 
manuring is meant to apply to farm-yard manure itself. 
The latter is the type of a valuable manure which cannot 
be replaced in every respect by any artificial mixtures 
in use. The remarks of the author only apply to the 
fallacious hopes entertained of keeping up permanently 
the fertility of the soil by manure obtained by the 
system of rotation, whilst we continue still to sell the 
corn raised by such manure without bringing back to 
the soil any portion of the mineral matter sold with 
the corn and cattle. 

The excrements of man contain all the mineral matter 
not only of the corn, but also of the cattle sold from 
the land. Could we restore these excrements to the 
soil, a perfect circulation of the conditions of hfe for 
plants and animals would be established, and our fields 
would be retained in a permanent state of fertihty. 
This problem has been solved by the Chinese and 
Japanese. Chinese rural life, as it is described by 
travellers, as well as the report of the Japanese system 
of husbandry given in Appendix G. by Dr. Maron, 
would scarcely lead us to wish for the improvement 
of agriculture upon the plan of these Orientals ! The 
requirements of modern civilisation would not permit 



EDITORS PREFACE. IX 

the purchase of manuring matter, however valuable, 
at the cost of all domestic comfort. The sewers must, 
we fear, still receive what would be offensive to our 
English senses. But can the contents of these sewers 
not be made available ? The great mass of water which 
necessarily accompanies at present the fertilising matters, 
renders them of comparatively little value when com- 
pared with the expense of transport. But how to 
separate and concentrate these matters from the water 
is a problem which is at present occupying the earnest 
attention of scientific and practical men. The solutions 
hitherto proposed are far from satisfactory. The future 
of agriculture is, however, intimately connected with 
the right solution of this great sewage question. 

In conclusion, I have only to state that the foreign 
weights and measures have been, when necessary, trans- 
lated into their equivalents in English, but have been 
left unaltered when the point was only one of comparison, 
which could be equally illustrated by the foreign weights. 



J. BLYTH, M.D. 



Queen's College, Cork: 
March 16, 1863. 



PEEFACE. 



IN the sixteen years wliich have intervened between 
this work and the sixth edition of my ' Chemistry 
apphed to Agriculture and Pliysiology,' I have had 
sufficient opportunity to become acquainted with ah 
the obstacles which are opposed to the introduction 
of scientific teaching into the domain of practical 
agriculture. Among the chief of these may be reckoned 
the complete separation which has always existed between 
science and practice. 

There has generally prevailed an idea that a smaller 
amount of information and intelligence is required for 
agricultural pursuits than for any other occupation ; nay, 
that the practical skill of the farmer is only likely to 
be injured when he has recourse to science. Whatever 
requires thought and reflection is regarded as theory, 
which being the opposite of practice, must, of course, be 
of httle value. The natural result of such opinions is, 
that when the practical man does attempt to apply 
scientific teaching, he is almost invariably a sufferer. 
He seems altogether to forget that man does not become 
intuitively acquainted with scientific teaching, which, 
like the skilful use of any complex instrument, must be 
learned. 



XU PEEFACE. 

The truth or error of the notions which guide our 
practice cannot, however, be regarded as a matter of 
indifference. 

The more correct ideas wliich science has given us of 
the growth of plants, and the part played in the process 
by the soil, air, mechanical operations, and manure, is 
not regarded in the hght of an improvement by the 
practical man, simply because his ignorance does not 
enable him to appreciate the information. Unable to 
find out the connection between scientific teaching and the 
phenomena presented in his daily pursuit, he naturally 
comes to the conclusion, from his point of view, that 
there really exists no connection between them. 

The practical agriculturist is guided by facts observed 
in his own neighbourhood for a long period ; or, 
if his views are more comprehensive, he follows 
certain authorities whose system of husbandry is held 
to be the best. It never enters into his thoughts to 
submit this system to proof, for he has no standard of 
comparison at hand. What Tliaer discovered to be 
useful in Moglin was held to be equally so for all 
Germany, and the facts which Lawes found to be true 
on a very small piece of land at Eothamsted have 
.become axioms for all England. 

Under the dominion of tradition and of slavish sub- 
mission to authority, the practical man has lost the faculty 
of forming a right conception of the facts which daily 
pass before his eyes, and in the end can no longer 
distinguish facts from opinions. Hence, when science 
rejects his explanations of any particular facts^ it is 



PEEFACE. XIU 

asserted that the facts are themselves denied. If science 
declares that we have made progress in substituting 
for deficient farm-yard manure its active ingredients, or 
that superphosphate of hme is no special manure for 
turnips nor ammonia for corn, it is imagined that the 
utility of these substances is contested. 

Long disputes have arisen about misconceptions of 
this kind. The practical man does not understand the 
inferences of science, and considers himself bound to 
defend his own views. The contest is not about scientific 
principles, which he does not understand, but about the 
false conceptions he has formed of them. 

Until this contest is ended by agriculturists themselves 
taking an active part in the matter, science can offer no 
effectual aid. I am doubtful if this time has yet arrived. 
I build my hopes, however, on the young generation 
who enter upon practice with a different preparation 
from their fathers. As for myself, I have reached the 
age when the elements of the mortal body betray a 
certain tendency to commence a new circle of action, 
when we begin to think about putting our house in 
order, and must defer to no later period what we have 
still to say. 

As every investigation in agriculture requires a year 
before we have all the facts before us, I have scarcely 
any prospect of living to see the results of my teaching. 
The only thing that remains for me to do, under these 
circumstances, is to place my views in such a manner 
before the public, that there can be no possibility of 
misconception on the part of those who will give them- 



XIV PEEFACE. 

selves the trouble of becoming thoroughly acquainted 
with them. 

Many have reproached me with unjustly condemning 
modern agriculture as a system of exhaustion. From 
the communications addressed to me by many agricul- 
turists as to their system of husbandry, I must exempt 
them from such an accusation. There are, however, 
but few among the general body who really know the 
true condition of their soil. 

I have never yet met with an agriculturist who kept a 
ledger, as is done as a matter of course in other industrial 
pursuits, in which the debtor and creditor account of 
every acre of land is entered. 

The opinions of practical men seem to be inherited 
hke some inveterate disease. Each regards agriculture 
from his own narrow point of view, and forms his con- 
clusions of the proceedings of others from what he does 
himself 

JUSTUS YON LIEBia. 

Munich: Mm-ch 1863. 



CONTENTS. 

CHAPTER I. 

THE PLAJSfT. 

Chemical and cosmic conditions of the life of plants — Conditions for the 
germination of the seed ; moisture and oxygen, their action — Influence of 
the seed in the formation of the organs of absorption, and the production 
of varieties ; influence of climate and soil in producing varieties — Im- 
portance of a knowledge of the developement of roots ; radication of 
difierent plants — Comparison of the process of vegetation in annual, 
biennial and perennial plants — Growth of the asparagus, as an example 
of a perennial pla: .': ; storing of reserve food in its underground organs; 
use of this store — Meadow and woody plants — Growth of biennial 
plants ; turnips : Anderson's experiments — Growth of annual plants ; 
summer plants : tobacco ; winter wheat, its developement like biennial 
plants; oats: AiV;dt's experiments; Knopp's experiments with maize in 
flower — The protoplastem (matter for forming cells) ; conditions for its 
formation; Boussingaidt's experiments; organic processes in plants, 
directed to the formation of the protoplastem — Absorption of food by 
plants not an osmotic process ; marine-plants ; duck -weed ; land-plants ; 
Hale's experiments on absorption by the roots and evaporation from the 
leaves — Power of the root to exclude certain substances from absorption 
not absolute ; Forchhammer, Knopp — Comportment of the roots of land 
and water plants to solutions of salts ; De Saussure, Schlossberger ; com- 
portment of land-plants to solutions of salts in the soil — Use of those 
mineral matters which are constant in difierent species of plants : iron, 
magnesia, iodine, and chlorine compounds — Absoi-ption of matters by 
plants from the surrounding medium ; influence of the consumption of them 
by the plant ; part played by the roots in their absorption . page 1 

CHAPTER II. 

THE SOIL. 

The soil contains the food of plants — Soil and subsoil ; conversion of the 
latter into the former — Power of the soil to withdraw the food of 
plants from solution in pure and in carbonic acid water ; similar action of 
charcoal ; process of surface attraction ; chemical decomposition often 
accompanies this attraction of the food of plants in the soil ; general 
resemblance of the soil in its action to animal charcoal — All arable soils 



XVI CONTENTS. 



CHAPTER 11.— continued. 



possess the power of absorption, but in different degrees — Mode of tbe 
distribution of the food of plants in the soil ; chemically and physically 
fixed condition of the food — Only the physically fixed are available to 
plants, being made soluble by the roots — Power of the soil to nourish 
plants; on what dependent — Comportment of an exhaiisted soil in 
fallow — Means for making the chemically fixed elements of food avail- 
able to plants — Action of air, weather, decaying organic matters and 
chemical means — Distribution of phosphoric and silicic acids ; influence 
of organic matters — Action of lime — Process of the absorption of food 
from the soil by the extremities of the roots — Mechanical preparation of 
the soil ; its influence on the growth of plants ; chemical means for pre- 
paring the soil — Rotation of crops ; its influence on the quality of the 
soil; action of draining — Plants do not receive their food from a solu- 
tion circulating in the soil ; examination of drain, lysimeter, spring and 
river water : bog water, food of plants contained in it ; Briickenauer 
spring water contains volatile fatty acids ; amount of food of plants in 
natural waters dependent on the nature of the soil through which they 
flow — Mud and bog earth as manure ; explanation of their action — 
Manner in which plants take up their food from the soil ; experiments on 
the growth of plants in solutions containing their food ; similar experi- 
ments with soil containing the food in a physically fixed state — Intimate 
connection of natural laws — Average crop ; necessary quantity of assimi- 
lable food in the soil for the production of such ; importance of the ex- 
tent of surface of the food in the soil; the root surface — Quantity of 
food for a given surface of roots necessary for a wheat or rye crop — 
Analysis of the soil of a field — Diftereuce between fertility and produc- 
tive power of a field — Mode of estimating relative extent of root sur- 
faces — Conversion of rye into wheat soil ; quantity of food necessary for 
the pui-pose ; the plan impracticable — Immobility in the soil of the food 
of plants ; experience in agriculture — Real and ideal maximum produc- 
tion — Conversion in practice of the chemically fixed food into an available 
form — Effect of a manure depends upon the property of the soil — 
Improper relative proportions of the different elements of food in the 
soil : effect of this upon the different cultivated plants : means for restor- 
ing the proper relative proportions .... page G2 

CHAPTEE III. 

ACTION OF SOIL ON FOOD OF PLANTS IN MANUEE. 

Manures : meaning of the term; their action as food of plants and means 
for improving the soil — Effect on soils with different powers of ab- 
sorption — Each soil possesses a definite power of absorption ; the dis- 
tribution of the food of plants in the soil is in^-ersely to the power of 
absorption; means of counteracting the absorptive power — Absorption 
number, notion of ; comparison of in different fields ; its importance in 
husbandry — Soil saturated with food of plants ; its comportment with 
water — Qiumtitv of food to saturate a soil — A saturated soil not 



CONTENTS. XVll 

CHAPTER IlL—cmiimied. 

required for the growtli of plants — Manuring may be compared to the 
application of earth saturated with food — Importance of the uniform 
distribution of food in manures; fresh and rotted stall manure; compost; 
importance of powdered turf for the preparation of manure — Quantity 
of food in unmanured fields and their powers of production ; increase of 
the latter apparently out of proportion to the manure added ; experiments 
on this point ; explanation ; composition of the soil and its absorptive 
power compared with the requirements of the plants to be cultivated on 
it; surface and subsoil plants, the tillage and manuring respectively 
required by each — Clover sickness ; experiments of Gilbert and Lawes ; 
their conclusions ; value of them .... page 131 

CHAPTEK IV. 

FAEM-TARD MANUEE. 

The fertility of a soil depends upon the sum of available food, the continu- 
ance of the fertility upon the total amoimt of all food in it — Chemical 
and agricultural exhaustion of the soil — Exhaustion of the soil by culti- 
vation, laws regulating its progression; eiFect of the transformation in 
the soil of the chemically fixed into physically fixed elements of food; 
effect on the progress of exhaustion by partial restoration of the with- 
drawn food of plants — Progress of the exhaustion by different cultivated 
plants — Cultivation of cereals, consequence of removing the grain and 
leaving the straw in the soil; intervening- clover and potato crops; 
eiFect of leaving in the ground the whole or a portion of these crops ; 
division of soils ; productive power of wheat fields increased by accumu- 
lating in them the materials derived from clover and potato fields : cul- 
tivation of fodder plants ; their food partly derived from the subsoil ; 
addition of these increases the productive power of the surface soil — 
Natural connection between the cultivation of cereals and fodder plants, 
the influence on the fertility of land — Exhaustion of the soil removed 
by the restoration of the withdrawn mineral constituents ; the excrement 
of men and animals contains these ; their restoration depends upon the 
agriculturist . . . . . . ... 165 

CHAPTER V. 

THE SYSTEM OF FAEM-YAED MANUEING. 

Questions to be solved — Experiments of Eenning, their sig-nificance — 
Produce of immanm-ed fields — Influence of preceding crops, of the situ- 
ation, and climatic conditions, on the produce — Each field possesses its 
own power of production — Large crops, their dependence and continua- 
tion — Closeness of the food of plants, what is meant thereby — The 
closeness of the particles of food in the soil is in proportion to the pro- 
duce — Produce of com and straw influenced by the relations of the 
assimilated food and by the conditions of growth ; action of food sup- 
plied in manures — Potatoes, oats, and clover crops of the Saxon fields ; 

/ 



XVni CONTENTS. 



CHAPTER ^.—continued. 



conclusions drawn from them as to tlie condition of tlie fields — Produce 
of these fields from farm-yard manure ; the increase of produce cannot he 
calculated from the amount of manure used — Restoration of the power of 
production of exhausted fields hy the increase of the necessary elements of 
food present in the soil in minimum amount; advantageous use of farm-yard 
manure in this respect; explanation of the result — Action of manure as 
compared with quantity used: experiments — Rational system of cultivation 
— Depth to which the food of plants penetrates is dependent on the power 
of ahsorption of the soil; the Saxon fields considered in this respect ; the 
power of absorption considered in manuring — Change produced in the 
composition of the soil by the system of farm-yard manuring ; the dif- 
ferent stages of this system, the final result — Examples of these stages in 
the Saxon experimental fields — Cause of the growth of weeds ; reme- 
dies — The history of husbandry, what is taught by it — Present condi- 
tion of European husbandry — Present production of the land compared 
with the earlier ; conclusions — Continuation of production regulated by 
a natural law — Law of restoration ; defective practice of it — Agricul- 
ture in the time of Charlemagne — Agriculture in the Palatinate — Corn 
fields in the valleys of the Nile and Ganges ; nature provides in them for 
the restoration of food of plants — Practical agriculture and the law of 
restoration — The statistical returns of average crops afibrd an explana- 
tion of the condition of corn fields .... page 188 

CHAPTEE VI. 

GUANO. 

Composition compared with that of seeds ; small amoimt of potash in it ; 
its action — Guano and bone-earth, similarity of their active ingredients 
— Guano acts quicker than bone-earth, or a mixture of the latter and 
ammoniacal salts ; reason of this — Oxalic acid in Peruvian guano ; the 
phosphoric acid rendered soluble by its means — Peruvian guano, its effect 
on the cultivation of corn — Moist guano loses ammonia — Moistening 
guano with vpater acidulated -oath sulphuric acid; effect — Inactivity of 
guano in dry and very wet weather — Rapidity of its action as a manure, 
on what dependent ■ — ■ Comparison of the effect of farm-yard manure 
and guano ; eifect produced by mixing the two — Guano on a field rich 
in ammonia — Increased produce by guano, what it presupposes — 
Exhaustion of the soil by continuous use of guano — Mixture of giiano 
with gypsum and ^dth sulphuric acid — The Saxon agricultural experi- 
ments ; their results ....... 256 

CHAPTEE VII. 

POUDBETTE HUMAN EXCEEMENTS. 

Poudrctte, nature of; small amount of the food of plants in it — Human 
excrement, its value — Construction of the privies in the barracks at 
Eastadt — Calculation of the amount of corn produced by the excrement 
collected ; importance to the neighbourhood — Its eifect not impaired by 
deodorising with sulphate of iron — The excrement of the inhabitants of 
towns as manure — Its importance ..... 271 



CONTENTS. Xix 

CHAPTER VIII. 

EARTHY PHOSPHATES. 

High agricultural value of phosphates — Phosphates of commerce ; selection 
of the kind to be used dependent on the object in view, and on the nature 
of the soil — The rapidity and the duration of the effect of the neutral 
and of the soluble phosphate (superphosphate) of lime — The Saxon 
manm-ing experiments ..... page 276 

CHAPTER IX. 

GROUND RAPE-CAKE. 

Nature and composition of; the diffiisibility of its constituents in the soil is 
comparatively great — Its importance as a manuring agent is small — 
The Saxon agricultural experiments with rape-cake — The inferences from 
them ......... 282 

CHAPTER X. 

WOOD-ASH. 

The anioimt of the food of plants in it — Box-wood ash gives only the half 
of its potash readily to water — Convenience in mixing wood-ash with 
earth before applying it — Lixiviated ash, its value — Proper mode of 
applying ashes as a manure ...... 287 

CHAPTER XL 

AMMONIA AND NITRIC ACID. 

Source of the nitrogen of plants — Amount of ammonia and nitric acid in 
rain and dew : Bineau, Boussingault, Knop — Quantity of ammonia in the 
air — Quantity of nitrogenous food brought to the soil yearly by rain and 
dew; more present in the soil than is removed by the crops — The 
general reason for decrease of productive power in soils — Classification 
of manures according to the amount of nitrogen; assimilable and spar- 
ingly assimilable nitrogen ; the nitrogen theory ; only ammonia according 
to this theory is wanting ; resemblance to the humus theory — Manuring 
experiments with compounds of ammonia by Schattenmann, by Lawes 
and Gilbert, by the Agricultural Union of Munich, and by Kuhlmann — 
The efficacy of a manure is not in proportion to its amount of nitrogen : 
experiments — Large amount of nitrogen in soils ; the experiments of 
Schmid and Pierre ; the arable surface soil contains most nitrogen — 
Form of the ammonia in the soil ; Mayer's experiments — Comportment 
of soil and farm-yard manure with the alkalies — The ineffective nitrogen 
of the soil made effective by the supply of ash-constituents that are 



XX CONTENTS. 



CHAPTEE XI.— continued. 



wanting — Progress in agriculture impossible if dependent on a supply 
of ammoniacal compounds; results of Lawes' experiments with salts of 
ammonia — The artificial supply of ammonical manures contrasted with 
the crops produced and the increase of populatii^n — Increase of nitro- 
genous food by natural means ; formation of nitrite of ammonia by oxi- 
dation in the air according to Schonbeim — Supply of food in excess neces- 
sary to produce corn-crops ; reasons — How the necessary excess of nitro- 
genous food for corn may be obtained from natural sources — The supply 
of nitrogen in farm-yard manure in the Saxon experiments corresponded 
to the crop of clover-hay — Loss of nitrogen in lime soils by oxidation ; 
utility of a supply of nitrogen to such soils — Effect of nitrogenous food 
on the aspect of young plants ; on potatoes — Empirical and rational 
systems of agriculture ..... page 289 



CHAPTEE XII. 

COMMON SALT, NITRATE OF SODA, SALTS OF AMMONIA, 
GYPSUM, LIME. 

Effect of these substances as elements of food ; their effect on the condition 
of the soil — Kuhlmann's experiments with common salt, nitrate of soda, 
and salts of ammonia; experiments with the same substances in Bavaria ; 
conclusions : these matters are elements of food ; they are chemical 
means for preparing the soil ; they cause the distribution of the food in 
the soil in the form proper for the gTOwth of plants — Experiments by 
Pincus with gypsum and sulphate of magnesia on clover ; decrease of 
flowers and increase of stem and leaves of clover by sulphates ; the crop 
is not in proportion to the quantity of sulphates used — Effect of gypsum 
not yet explained ; indication in the comportment of clover soils with 
solution of gypsum ; such solution dispei-ses potash and magnesia in the 
soil — Manures, their effect not explained by the composition of plants 
produced by them — Composition of the ash of clover manured with dif- 
ferent substances — Effect of lime ; experiments of Kuhlmann and Trager ; 
comportment of lime-water with soils .... 335 



APPENDICES. 

Beech leaves and asparagus, their ash-constituents at different periods of 
growth — The amylum of the palm — Motion of sap in plants — Drain, 
l3rsimeter, river, and bog water, their constituents — Fontinalis antipyi'etica 
from two different waters, ash-constituents — Vegetation of maize in 
solutions of its food — Experiments on the growth of beans in pure and 
prepared tm-f, results — Japanese agriculture — The cultivated soil of 
the torrid zone, its exhaustibility, its manure — Analysis of clover by 
Pincus — Clover sickness, its causes ..... 353 



THE 



NATURAL LAWS OP HUSBANDRY, 



CHAPTEE I. 

THE PLAINT. 

Chemical and cosmic conditions of the life of plants — Conditions for the 
germination of the seed ; moisture and oxygen, their action — Influence of 
the seed in the formation of the organs of absorption, and the production 
of varieties ; influence of climate and soil in producing varieties — Im- 
portance of a knowledge of the developement of roots; radication of 
different plants — Comparison of the process of vegetation in annual, 
biennial and perennial plants — Growth of the asparagus, as an example 
of a perennial plant ; storing of reserve food in its imderground organs ; 
use of this store — Meadow and woody plants — Growth of biennial 
plants ; turnips : Anderson's experiments — Growth of annual plants ; 
summer plants : tobacco ; winter wheat, its developement like biennial 
plants ; oats : Arendt's experiments ; Knopp's experiments with maize in 
flower — The protoplastem (matter for forming cells) ; conditions for its 
formation; Boussingault's experiments; organic processes in plants, 
directed to the formation of the protoplastem — Absorption of food by 
plants not an osmotic process ; marine-plants ; duck-weed ; land-plants ; 
Hale's experiments on absorption by the roots and evaporation from the 
leaves — Power of the root to exclude certain substances from absorption 
not absolute; Forchhammer, Knopp — Comportment of the roots of land 
and water plants to solutions of salts ; De Saussure, Schlossberger ; com- 
portment of land-plants to solutions of salts in the soil — Use of those 
mineral matters which are constant in different species of plants : iron, 
magnesia, iodine, and chlorine compounds — Absorption of matters by 
plants from the surrounding medium ; influence of the consumption of them 
by the plant ; part played by the roots in their absorption. 

rriO obtain a clear view of the theory and practice of 
-^ Agriculture, we must keep in mind the most general 
chemical conditions of the life of plants. 

B 



2 THE PLANT. 

Plants contain combustible and incombustible consti- 
tuents. Of the latter, which compose the ash left by all 
parts of a plant on combustion, the most essential ele- 
ments are — phosphoric acid, sulp)huric acid, silicic acid, 
potash, soda, lime, magnesia, iron, and chloride of lodium. 

The combustible constituents are derived from carbonic 
acid, ammonia, sulphuric acid, and water. 

By the vital process of vegetation, the body of the 
plant is formed from these materials, which are therefore 
caUed the food of plants. All the materials constituting 
the food of our cultivated plants belong to the mineral 
kingdom. The gaseous elements are absorbed by the 
leaves, the fixed elements by the roots ; the former, 
however, being often constituents of the soil also, may 
reach the plant by the roots, as well as by the leaves. 

The gaseous elements form component parts of the at- 
mosphere, and are, from their nature, in continual motion. 
The fixed elements are, in the case of land-plants, consti- 
tuents of the soil, and cannot of themselves leave the spot 
in which they are found. The cosmic conditions of vege- 
table life are heat and sunlight. 

By the cooperation of the cosmic and the chemical con- 
ditions, the perfect plant is developed from the germ or 
seed. The seed contains, within its own substance, the 
elements required to form the organs which are intended 
to take up food from the air and the soil. These elements 
are nitrogenous substances, similar in composition to the 
casein of milk or the albumen of the blood ; and also 
starch, fat, gum, or sugar, yn\\\ a certain quantity of earthy 
phosphates and alkaline salts. The farinaceous body, or 
so-called albumen, of the seed of corn, as also the consti- 
tuents of the cotyledons in leguminous plants, become the 
roots and leaves of the nascent plant. If corn-seeds are 
set to germinate in water, and allowed to grow upon a 



GERMINATION AND GEOWTH OF THE SEED. 3 

glass plate furnished with fine perforations, through which 
the roots may reach the water, the grain will go on grow- 
ing for several weeks without receiving any incombustible 
element of food or any constituent of the soil. After three 
or four weeks the apex of the first leaf is seen to turn 
yellow ; and upon examining the seed, nothing but an 
empty skin is found, for the starch has disappeared to- 
gether with the cellulose (Mitscherlich). However, the 
plant does not die away, but .new leaves are produced, 
often also a feeble stalk ; the constituents of the first- 
formed, but now withering, leaves being applied to the 
formation of fresh shoots. 

Under favourable circumstances, seeds with very large 
and vigorous cotyledons abounding in nutritive matter 
(e. g. beans) may, by vegetation in water alone, be got to 
flower — nay, even actually to produce small seeds ; this 
developement, however, is mostly unattended by a per- 
ceptible increase of substance, but depends solely upon a 
mere transposition of the elements of the seed. 

Nutrition is a process by which food is assimilated ; a 
plant grows when its mass is augmented, and its mass 
is increased by absorbing materials from without, which 
-are, from their nature, suited to become constituent 
elements of the body of the plant, and to sustain those 
functions upon which their assimilation depends. 

The bud on a potato-tuber stands in the same relation 
to the constituents of the tuber as the germ in a corn- 
seed does to the farinaceous matter of the albumen. 
While the bud is developed in the formation of the 
young plant, the amylum and the nitrogenous and 
mineral constituents of the sap of the tuber are employed 
to form the young branches and leaves. A potato, 
which lay wrapt up in thick paper, in a box, in the 
Chemical Laboratory at Giessen — in a place absolutely 

B 2 



4 THE PLANT. 

dark, dry, and warm, where the atmosphere was seldom 
changed — was found to have produced, from each bud, 
a simple white shoot many feet long, showing no traces 
of leaves, but covered with hundreds of minute potatoes, 
which exhibited the same internal structure as tubers 
grown in a field ; the cells consisted of cellulose, and 
were filled with minute starch granules. It is certain 
that the starch of the mother tuber, to have moved away 
from its position, must have become soluble ; but it is 
equally clear, that in the developement of the shoots a 
cause was operative within them, which (in the absence 
of all outward causes whereon growth depends) recon- 
verted the dissolved constituents of the mother tuber 
into cellulose and starch granules. 

The conditions required for the germination of a seed 
are — moisture, a certain degree of heat, and access of 
air ; where one of these conditions is excluded, the seed 
will not germinate. By the influence of the moisture 
which the seed absorbs, and which causes it to sweU, a 
chemical action takes place in it ; one of the nitrogenous 
constituents acts upon the others, and upon the amylum, 
so that by a transposition of the elementary particles, 
the constituents are rendered soluble ; the gluten is 
converted into vegetable albumen ; the amylum and oil 
into sugar. If the oxygen of the air is excluded, the 
changes either do not take place or they proceed in a 
different way. The seeds of land-plants, when submersed 
under water, or placed in a soil covered with stagnant 
water, which excludes the air, will not put forth their 
plumules. This is the cause why many seeds, lying deep 
in the ground or in bogs, will remain for many years 
without germinating, although the conditions of moisture 
and temperature be favourable. It is often found that 
earth taken up from bogs, or brought up by the plough 



PEOCESS OF GEEMINATION. 5 

from the deep subsoil, and exposed to the atmosphere, 
becomes covered with vegetation, arising from seeds 
which, for their developement, required free access of air. 
Lowness of temperature tends to annul or retard the 
influence of the air upon the process of germination ; 
whilst increase of temperature, with a proper supply of 
moisture, accelerates the chemical changes in the seed. 
No seed germinates below 32° Fahrenheit ; each ger- 
minates at a definite temperature, and therefore in fixed 
seasons of the year. The seeds of Vicia fqba, Phaseolus 
vulgaris^ and the poppy, lose the power of germinating 
when dried at 95° Fahrenheit; while barley, maize, 
lentil, hemp, and lettuce seed retain the power at that 
heat ; but wheat, rye, vetch, and cabbage seed will 
germinate even at 158° Fahrenheit. 

During germination, oxygen is taken up from the air 
around the seed, and an equal volume of carbonic acid is 
evolved. 

If seeds are set to germinate in glasses, with a slip of 
litmus paper fastened on the inside, the paper is red- 
dened, often after a very short time, owing to the dis- 
engagement of acetic acid : the most abundant and rapid 
evolution of free acid was found to take jok^ce in the 
germination of cruciferous plants, cabbage, and rape- 
seed (Becquerel, Edwards). Certain it is that the fluid 
contents of the cells of the roots, as well as the sap of 
most plants, have an acid reaction, from the presence of a 
non-volatile acid ; the sap of the young spring shoots of 
the vine yields, upon evaporation, an abundant crystallisa- 
tion of bitartrate of potash. 

By the experiments of Decandolle and Macaire, which 
have not yet been controverted, it was shown that vigorous 
plants of Chondrilla muralis and Phaseolus vulgaris which 
had been taken from the ground, with their roots, and 



6 THE PLANT. 

were allowed to vegetate in water, imparted to the water, 
after a week's time, a yellowish tint, a smell like that of 
opium, and a harsh taste : whereas when the root was 
cut off at the stalk and both were placed in water, no 
such substances were given off as those which the entire 
plant had yielded. 

Lettuces and other plants, when taken out of the 
ground, and, with their roots previously washed clean, 
are allowed to vegetate in blue htmus tincture, will con- 
tinue to grow in the liquid, apparently at the expense of 
the constituents of the lower leaves, which wither away. 
After three or four days the litmus tincture assumes a red 
colour, which, however, disappears again upon boihng the 
fluid : this would seem to indicate that the roots had given 
off carbonic acid. If the plants are left longer in the 
litmus tincture, the latter suffers decomposition, and be- 
comes neutral and colourless, while the colouring matter, 
separating in flakes, gathers round the fibres of the 
roots. 

The developement of a plant depends upon its first 
radication, and the choice of proper seeds is therefore of 
the highest importance for the future plant. A crop of 
the same wheat, reaped in the same year, and from the 
same field, will exhibit difierences in the size of the 
grains, some being larger, others smaller; and among 
both kinds, some when broken up vnil present a mealy, 
others a horny appearance, the one being more, the others 
less completely developed. The cause is this — that the 
stalks in the same field do not all shoot into ear and 
flower at the same time, and that some of them produce 
seeds much more maturely tlian others : hence the seeds 
of the one are far more developed, even in unfavourable 
weather, than the seeds of tlie others. A mixture of 
seeds unequal in their developement, or differing in the 



IMPORTANCE OF GOOD SEEDS. 7 

quantities of amylum, gluten, and inorganic matters wliicli 
tliey severally contain, wiU produce a crop of plants as 
unequal in their developement as tlie original seeds from 
which tliey sprung. 

The strength and number of the roots and leaves formed 
in the process of germination are (as regards the non- 
nitrogenous constituents) m direct proportion t.o the 
amount of amylum in the original seed. A seed poor 
in amylum will, indeed, germinate in the same fashion as 
another seed abounding in it ; but by the time the former 
has succeeded, by the absorption of food from without, in 
producing roots and leaves as strong and numerous, the 
plant grown from the more amylaceous seed is again just 
as much more advanced in growth : its food-absorbing 
surface was larger from the beginning, and the growth of 
the young plant is in like proportion. 

Poor and sickly seeds will produce stunted plants, 
which again will yield seeds bearing in a great measm^e 
the same character. 

The horticulturist knows the natural relation which the 
condition of the seed bears to the production of a plant, 
which is to possess all or only some properties of the 
species : just as the cattle-breeder, who, with a view to pro- 
pagation and increase of stock, selects only the healthiest 
and best-formed animals for his purpose; the gardener 
is aware that the flat and shining seeds in the pod of a 
stock gilly-flower will give tall plants with single fiowers, 
while the shjivelled seeds will furnish low plants with 
double flowers throughout. 

The influence of soil and climate gives rise to different 
varieties of plants, which, hke races, are possessed of 
certain peculiarities, and are propagated by means of seed, 
as long as the conditions remain the same. Planted in 
another soil, or in a different climate, the new variety will 



8 THE PLANT. 

lose again some one or other of its distinguishing charac- 
teristics. 

The influence exerted by the condition of the soil in 
producing varieties of plants is observed most frequently 
with seeds that pass undigested through the intestinal 
canal of animals which have eaten them, and then receive 
a different manuring, according to the various nature of 
the excrements of divers animals with which they are 
returned to the soil : an instance is afforded by the 
Byrsonima verhascifolia (v. Martins), 

In the selection of seeds for planting, it is always 
important to take into account the soil and climate from 
which they have been derived. In England seed-wheat 
from a poor soil is considered particularly well suited to a 
rich soil ; rape-seed grown in colder regions or situations 
is sure to give a good crop in warmer localities. Clover 
seed and oats from mountainous districts are preferred to 
the same seeds from plains. Wheat from Odessa and 
from South Hungary is esteemed in colder regions also. 
The planters on the Upper Ehine import their hemp -seed 
from Bologna and Ferrara. 

In like manner many German flax-growers, who wish 
to produce tall plants of uniform size, attach particular 
value to linseed from Courland and Livonia, where the 
soil and the nature of the climate, especially the short 
hot summer, bring the flowering and fruit time near 
together ; so that the flowers, being simultaneously and 
uniformly fructified, produce ripe and perfect seedvS. 

Everyone knows how much the weather, during the 
flowering period, uifluences the formation of seed. If, 
after the flowering has commenced, cold weather or rain 
sets in, retarding the fuU developement of the inflorescence, 
the flowers fertilised at a later period produce no seeds, 
as the nutriment needed by them is applied by the 



EADICATION OF PLANTS. 9 

flowers first fertilised for their own developement. It is 
a fact, that many plants will not repay the trouble of cul- 
tivation, if the chmatic conditions are not sufficiently 
favourable to effect the thorough ripening of all the 
flowers, but serve only to ripen part of them. 

With oats it often happens that in warm moist weather 
side-branches will spring from the axils of the leaves, 
when the principal culm is already shooting into ear ; 
whence it happens, that at the end of the period of vegeta- 
tion the plant is found to bear both ripe and unripe seeds. 

The condition of the soil, as to porosity or compactness, 
influences the radication of plants. The fine filaments of 
the root, which are often coated with cork-like matter, 
are lengthened by the formation of new cells at their 
extremities, and they are obliged to exert a certain pres- 
sure, to force their way through the particles of earth. 

The root-fibrils will always extend in that direction in 
which they encounter the least resistance ; and this 
lengthening necessarily presupposes that the pressure 
wherewith the new-formed cells push aside the particles 
of earth, must be somewhat greater than the cohesion of 
the particles. The strength with which the root-fibres 
force their way through the soil, is not equally great in 
all plants. Those plants which have roots formed of 
very fine fibres, are but imperfectly developed in stiff", 
heavy soils, wherein other plants with thicker and stiffer 
root-fibres will grow luxuriantly. The very resistance 
which the heavy soil opposes to the spreading of the 
roots of such plants tends to strengthen their fibres. 

Of the cereals, wheat, with a comparatively feeble 
ramification of roots in the upper layers of the soil, still 
forms the strongest roots, which often penetrate several 
feet down into the subsoil ; for a certain degree of com- 
pactness in the surface soil is favourable to the develope- 



10 THE PLANT. 

ment of its roots. There are instances on record, wliere 
parts of a wheat-field had been trampled down in the 
winter by horses (by no means an uncommon occurrence 
in the foxhunting districts of England), so far as to de- 
stroy every trace of a wheat-plant, and yet next year's 
crop turned out much more abundant on those very 
spots than in any other part of the field. It is evident 
that, to outlive an attack of this kind, a plant must have 
its principal roots spreading in the deeper layers of the 
soil. In the developement of its roots and the power 
of penetrating the deeper layers of the soil, the oat- 
plant stands next to wheat, and will flourisli in a 
somewhat stiff soil ; but as in the superficial layers 
also the roots of oats throw out a number of fine 
feeders, in a lateral direction, it is necessary that the top- 
soil should be rather light and open. A light, open 
loam, even if of no great depth, is particularly suited for 
barley, which forms a network of fine comparatively 
short root-fibres. Peas require a loose soil, Avith little 
cohesion about it, which will favour the spreading of the 
soft root-fibres in the deeper layers also ; whereas the 
strong woody roots of the horse-bean will ramify in all 
directions, even in a heavy and more compact soil. 
Clover, grass-seeds, and small-sized seeds in general, put 
forth at first feeble roots of small extent, and require so 
much the greater care in preparing the soil, in order to 
ensure their healthy growth. The pressiu-e of a layer 
of earth half to one inch thick sufiices to prevent the 
developement of the seed sown in the ground. Such 
seeds require only just as much earth to cover them as 
will retain the needful moisture for germination. It is, 
therefore, found advantageous to soav clover together 
with corn of some kind ; for as the corn is earlier and 
quicker in growth, its leaves shade the young clover 



THE EOOTS OF PLANTS AND THE SOIL. 11 

plant, and protect it from the too intense action of the 
sun's rays ; thus afibrding more time for the extension 
and developement of the roots. The nature of the roots* 
of rapes, turnips, and tuberous plants, clearly points out 
the part of the soil from which they draw their chief 
supply of food. Potatoes are formed in the topmost 
layer of the soil ; whereas the roots of beets and turnips, 
sending their ramifications deep into the subsoil, will 
succeed best in a loose soil of great depth. Still, they 
will also grow well in soil naturally heavy and compact, 
which has been properly prepared for their reception. 
Among turnips, the Swedish variety is distinguished by 
the numerous fibres which the root-stock sends into the 
ground ; and mangel wurzel, with its strong and rather 
woody root fibres, is still better suited than Swedes for 
a heavy clay soil. 

On the length of roots but few observations have been 
made. In some cases it has been found that lucerne will 
grow roots thirt}-" feet, rape above five feet, clover above 
six feet, lupine above seven feet in length. 

A proper knowledge of the radication of plants is the 
groundwork of agriculture ; all the operations which the 
farmer applies to his land must be adapted to the nature 
and conditions of the roots of the plants which he wishes 
to cultivate. On the root he should bestow his whole 
care ; upon that which grows from it he can no longer 
exert any influence ; therefore, to secure a favourable 
result to his labours, he should prepare the ground in a 
proper manner for the developement and action of the 
roots. The root is not merely the organ through which 
the growing plant takes up the incombustible elements of 
food required for its increase, but it may, in another 

* "Whenever the term ' root ' is used in this work, the iinderground 
organs of plants are meant. 



12 THE PLANT. 

not less important function, be compared to the flywheel 
in an engine, which gives regularity and uniformity to 
the working. It is in the root that the material is stored 
up to supply the growing plant with the needful elements 
for conducting the processes of life, according to the 
requirements made upon it by the action of light and heat. 

All plants which give landscapes their peculiar cha- 
racter, and clothe the plains and mountain slopes with 
perennial green, have an underground developement, 
according to the geological or physical condition of the 
soil, admirably adapted to their perennial existence and 
propagation. 

Whilst annuals are propagated and multiplied by seeds 
alone, and have always a true root easily known by its 
simplicity of structure, by the absence of buds, and by 
the comparatively short range of its fibres, the turf and 
meadow plants are propagated by shoots and runners of 
a peculiar nature, and in many of them propagation is 
independent of the formation of seed. 

As the strawberry, which will in a very short time 
cover extensive tracts of ground, sends forth from the 
stock above the root-bulb shoots in the shape of run- 
ners, which creeping along the ground, and producing 
here and there buds and roots, grow up as independent 
plants, so the perennial weeds, among which are here 
included the meadow and pasture plants, spread in a simi- 
lar manner by corresponding underground organs. The 
creeping roots of the couch-grass (Triticum repens), the 
sea lyme-grass (Elymus arenarius), the trefoil {Trifolium 
pratejise), the common toad-flax (Linaria vulgaris), pro- 
pagate their plants by suckers in all directions from the 
mother-plant. The smootli-stalked meadow-grass (Poa 
pratensis) is propagated by a mother-stock, consisting of 
true roots, rooted runners, and creeping suckers ; rye 



EADICATION OP DIFFERENT PLANTS. 13 

grass (Lolium) puts forth root-suckers in a stiff soil, and 
prostrate stolons in loose ground. Cat's-taii grass (Phleum) 
is found sometimes with bulbous, sometimes with fibrous 
many-headed roots, havmg a tendency to creep and to 
form mother-stocks. Timothy-grass grows stalk in the 
first year ; in the second, it forms sometimes bulbous, 
sometimes fibrous many-headed mother-stocks, which send 
forth creepers in all directions. In the same way, 
meadow-grass spreads partly by budding suckers, partly 
by stolons. 

On comparing the vital processes in annual, biennial, 
and perennial plants, we find that the organic work in 
perennials is principally directed to the formation of the 
root. 

The seed of asparagus sown during autumn, in a fertile 
soil, mil produce next year, from spring to the end of 
July, a plant about a foot high, the stem, twigs, and 
leaves of which from that time forward show no further 
increase. The tobacco plant, which is an annual, would 
from the same period to the end of August have pro- 
duced a stem several feet high, covered with numerous 
broad leaves ; and the turnip a broad crown of foliage. 

But the cessation in the growth of the asparagus plant 
is only apparent ; for from the moment that the external 
organs of nutrition are developed, the root increases in 
extent and substance in far greater proportion to the over- 
ground organs than is the case with the tobacco plant. 
The food which the leaves have absorbed from the air and 
the roots from the soil, having first been transformed 
mto organisable matter, descends to the roots, in which 
there is gradually collected a sufficient store to enable 
the latter to furnish in the following year from themselves 
and without the least supply of food from the atmosphere 
the material required for the production of a new perfect 



14 THE PLANT. 

plant, witli a stem half as high again and a much greater 
number of twigs and leaves. The organic labour of this 
new plant, during the second year, results in the genera- 
tion again of products which are deposited in the root, 
and, proportionately to the greater extent of the organs of 
nutrition, are stored up in much greater quantity than 
the roots had originally supplied. 

The same process is repeated in the third and fourth 
years ; in the fifth and sixth years the store deposited in 
the roots has become sufficiently rich to produce in spring, 
when the weather is warm, three, four, and more stems as 
thick as a finger, with numerous branches covered with 
leaves. 

A comparative examination of the green asparagus 
plant, and of its withering stems in_ autumn, seems to 
indicate that at the end of the period of vegetation the 
remainder of the dissolved or soluble substances fit for 
future use, then still remaining in the overground organs, 
descend to the root. The green parts of the plant are 
comparatively rich in nitrogen, alkahs, and phosphates, 
whilst in the Avithered stems these substances are found 
in small quantities only. The seeds alone retain compa- 
ratively large proportions of phosphated earth and alkalis, 
being nothing else than the excess of those substances 
which the roots do not require for the next year. 

The underground organs of perennial plants are the 
economic gatherers of all the vital conditions necessary 
for certain functions. If the soil will allow, they always 
collect more than they give out ; they never spend all 
they receive. These plants form their flowers and seeds 
when the roots have collected a certain excess of phos- 
phates, which may be given up without endangering the 
existence of the plant. An abundant supply of nourish- 
ment, by means of manuring, will accelerate the develope- 



PERENNIAL PLANTS. 15 

ment of the plant in one or another direction. Manuring 
a sward with ashes will draw from it clover plants ; if 
acid phosphate of hme is employed, French rye-grass will 
spring up in thickly serried blades. 

In all perennial plants, the underground organs are 
usually very much greater in mass and extent than those 
of annual plants. Whilst the roots of the latter die every 
year, the former preserve theirs in a state of readiness to 
absorb food at every favourable opportunity. 

The circle from which a perennial plant draws its food 
enlarges from year to year ; if one part of its roots finds 
little nourishment in a given spot, other parts draw their 
supply from other spots richer in the food required. 

Only a very small portion of the plants of a thickly 
covered meadow will produce stems ; the far greater part 
will develope only tufts of leaves ; and many will for years 
be confined to the production of underground suckers. 

For perennial grass and meadow plants, the production 
of underground suckers is of the highest importance, 
since by them the plant is furnished with nutriment at a 
time when a scarcity of supply would endanger the hfe of 
annual plants. 

A good soil, and all other conditions of vegetable life, 
will of course exert the same favourable influence • upon 
perennial as on annual plants ; but the developement of 
the former is not so much dependent upon accidental and 
passing states of the weather, as is the case with the 
latter. Unfavourable conditions will, indeed, check the 
growth of a perennial plant, but only for a time, until a 
favourable change ensues, when the plant will resume 
growing ; whereas an annual plant, under the same 
circumstances, reaches the hmits of its existence and dies. 

The permanence of vegetation on our meadows, and 
the certainty of their produce under varying conditions of 



16 THE PLANT. 

soil and weather, must be attributed to the great number 
of plants which are able to continue for a shorter or 
longer period at a low stage of developement. While the 
one species of plants is developed above ground, producing 
flowers and seeds, a second and third species gather 
below the surface the conditions for a similar future 
growth. The one vegetation seems to disappear, to make 
room for another and a third, until for itself too the con- 
ditions for a perfect developement recur. 

The woody plants grow and are developed in a manner 
quite similar to the asparagus plant, with this difference, 
however, that they do not lose their stem when the 
period of their vegetation comes to an end. An oak- 
sapling, 1^ foot high, was found to have a root above 
3 feet long. The stem and the root serve jointly as a 
magazine for storing up the organisable matter to be 
used next year in restoring all the external organs of 
nutrition. When the stems of lime trees, alders, or 
willows have been cut down, they will, if lying in shady 
moist places, shoot out afresh, often after the lapse of 
years, and produce numerous twigs a foot long or more, 
covered with leaves. 

The pauses which occur in the seed-bearing of forest 
trees are similar to those which are observed in most 
perennial plants, which, when growing on a poor soil, will 
also take several years to collect the conditions necessary 
for the production of fruit (Sendtner, Eatzeburg). 

The loss of inorganic food-constituents, which the 
fohaceous trees suffer by the fall of the leaves, is trifling. 
When the leaves have attained their full formation, the 
cells of the bark receive a copious supply of amylum, 
which substance completely disappears from the cells in 
the boss of the leaf-stalk (H. Molil). Even long before 
the fall of the leaves, their sap is considerably diminished. 



MINEKAL MATTEES IN FALLEN LEAVES. 17 

while the bark of the branches is, just at that time, often 
actually overflowing mth sap (H. Mohl). In accordance 
with this fact, the analysis of the ash of the leaves shows 
that the amount of alkah and phosphoric acid in them 
decreases immediately before the fall ; the fallen leaves 
contain such trifling quantities of these constituents, in 
comparison to their mass, that it is diflicult to account 
for the injurious consequences arising from the raking 
up and removal of the fallen leaves in woods. (See 
Appendix A.) 

A similar reflux of the assimilative products appears to 
take place in the grasses ; when from the intense heat of 
summer the leaves begin to decay, chemical analysis 
reveals in the yellow leaves scarcely any traces of nitrogen, 
phosphates, and alkalis ; and, indeed, animals instinctively 
turn from all kinds of fallen leaves, and refuse to feed on 
them. 

Li annuals and biennials the organic action results in 
the production of fruit and seed, after which the activity 
of the root comes to an end ; in perennials, the production 
of seed is rather an accidental condition of their permanent 
existence. 

The biennial can bestow more time than the amiual in 
gathering the material necessary for the production of 
seed and fruit, which closes the period of its existence ; 
but the time in which this takes place depends upon the 
state of the weather and the nature of the soil. 

The annual is uniformly developed in all its parts ; the 
food daily taken up is expended in increasing the over- 
ground and underground organs, which meanwhile take 
up a larger amount of food in proportion to the increase 
of their absorbent surface. With the growth of the 
plant, the conditions of increase inherent in the plant 

c 



18 THE PLANT. 

itself become enlarged, and exert their influence in pro- 
portion as the external conditions are favourable. 

The developement of the biennial plants cultivated for 
their roots has three distinct periods ; in the first period 
the leaves principaUy are formed ; in the second, the 
roots, in which are stored the substances needed to pro- 
duce the flower and fruit during the third period. 

A series of experiments, made by Anderson, upon 
turnips, afibrds a clear view of the several dhections in 
which the energy of a biennial plant tends at difierent 
periods of its growth. (' Journal of Agriculture and 
Transactions of the Highland Society,' No. 68, 69, new 
series, 5.) 

These experiments were made to ascertain the total 
produce of vegetable substances obtained from turnips on 
one acre of ground. The turnips were gathered at four 
different stages of growth ; the first on July 7, the 
second, on August 11, the third, on September 1, and 
the fourth, on October 5. The following table shows the 
weight of leaves and roots in pounds, taken up at the end 
of the respective stages, and calculated upon one acre of 
ground. 







Weiglit of leaves 


Weiglat of roots 


I. 


Harvest after 32 days . 


219 pounds 


7*2 pounds 


II. 


„ 67 „ . 


. 12,793 „ 


2,762 „ 


III. 


n 87 „ . 


. 19,200 „ 


14,400 


IV. 


122 „ . 


. 11,208 „ 


36,792 „ 



The relative quantities of leaves and roots show that in 
the first half of the time of vegetation, sixty-seven days, 
the organic labour in the turnip plant is principally 
directed to the production and developement of the ex- 



ternal organs. 



From the 7th July to the 11th August, a period of 
thirty-five days, we find the increase to be 12,574 pounds 



GROWTH OF TUENIPS. 19 

in the leaves, and 2,755 pounds in the roots, which gives 
a daily increase of 

Leaves Eoots 

359 pounds | 78 pounds 

In this stage, accordingly, the production of leaves 
prevailed over that of roots to this extent, that out of 
eleven parts of food absorbed by the plants, nine parts 
went to the leaves and only two parts to the roots. 

We find a very different proportion in the third stage ; 
for during twenty clays the weight of the leaves has 
increased by 6,507 pounds, that of the roots by 11,638 
pounds, which gives a daily increase of 

Leaves Roots 

325 pounds | 582 pounds 

During this third stage the plants take up daily somewhat 
more than double the amount of food taken up on any 
given day of the second stage, and this increase must 
stand in proportion to the daily enlargement of the surface 
of the roots and leaves ; but the food absorbed is dis- 
tributed in the plant in a very different manner. Of 
•twenty-five parts by weight of food absorbed and as- 
similated, nine parts only remain in the leaves, the other 
sixteen parts serve to increase the mass of roots. 

In exactly the same ratio as the leaves approached the 
limits of their developement, they lost the power of ap- 
plying to their further growth the food which they had 
absorbed, and which now transformed into organisable 
matter was deposited in the roots. The same nutritive 
particles which went to form leaves, so long as the mass 
of fohage kept on increasing, now became constituent 
portions of the root. 

This migration of the constituents of the leaves and 
transformation into constituents of the root appear to be 

c 2 



20 



THE PLANT. 



most clearly shown in the fourth stage. The total weight 
of leaves, which on the 1st September still amomited to 
19,200 pounds, had by the 5th October, or within the 
space of thirty-five days, decreased by 7,992 pounds, that 
is 228 pounds a day ; in other words, out of every thirty- 
four leaves ten had withered, while the roots had in- 
creased by 22,392 pounds, or 640 pounds a day — a daily 
increase much more considerable than during the third 
stage. 

It is evident that with the advance of autumn, with the 
lower temperature and diminished action of sunlight, the 
organic energy of the leaves decreased, and more than a 
third of the organisable matter collected in them de- 
scended to the roots, to be stored up for future use. 

If we compare the quantities of nitrogen, phosphoric 
acid, potash, common salt, and sulphuric acid, absorbed 
during the last ninety days by the. turnips growing on 
one acre of ground, we find from Anderson's experiments 
that the daily amount was as follows : — 



Abso7'bed ly the entire plant in a day. 



Total increase 


Second stage 


Third stage 


Fourth, stage 








Pounds 


In substance .... 


437 


907 


417 


Niti-ogen .... 


1-15 


0-695 


1-21 


Phosphoric acid 


0-924 


1-10 


1-25 


Potash .... 


1-41 


4-04 


3-07 


Sulphuric acid 


1-12 


1-57 


1-52 


Salt 


0-84 


1-98 


1-11 



Daily increase of roots in the fourth stage of growth. 



Supplied by the soil 
„ leaves 


Phosphoric acid 


Potash 


Sulphuric acid 


Salt 


1-25 
0-41 

1-G6 


3-07 
1-56 

4-63 


1-52 
0-51 

2-03 


1-10 
0-53 

1-63 



PHOSPHOEIC ACID AND POTASH IN GEOWING TUENIPS. 21 

These figures show that the quantity of phosphoric acid 
taken up daily by the turnip plants growing on one acre 
of ground increases from the commencement of the 
second to the end of the fourth stage of growth, that is 
in ninety days from 0*924 to 1-25 pound a-day, which 
reckoned from one day to another makes the trifling 
difference of 0-0037 pound a-day. 

Anderson suspects that his estimate of the nitrogen in 
the leaves during the third stage was not quite correct, 
and that it fell below the actual amount. If we add 
together the quantities of nitrogen absorbed in the last 
two stages, fifty-five days, we find a daily average of 1'02 
pound of nitrogen, which is very nearly the same as in 
the preceding stage of growth. 

The quantity of potash increased from the 11th August 
till the 1st September, in a somewhat higher ratio than 
the amount of vegetable substance produced. From the 
1st September till the 5th October the increase of the 
roots was nearly double what it had been in the preceding 
stage, but this is explained by the migration of the potash 
compounds from the leaves to the roots. It is evident 
that the increase of potash has a certain connection mth 
the formation of sugar and the other non-nitrogenous 
constituents of the roots, but no definite proportion can 
be estabhshed between them. The absorption of sul- 
phuric acid increased uniformly in the three last stages ; 
that of salt was a httle greater in the third than in the 
second and fourth stages. 

Without wishing to indicate the exact part performed 
in the process of vegetation by these various mineral 
substances, as also by lime, magnesia, and iron, we remark 
that, except in the case of potash, the absorption of them 
was evidently uniform from day to day, yet showing every 
day a trifling increase corresponding to the daily increase 



22 THE PLANT. 

of the food-absorbent surface up to the fourth stage of 
growth. 

The smallest increase was seen in phosphoric acid and 
nitrogen, both equally necessary for the formative pro- 
cesses going on in the turnip plant ; and it is manifest 
that they must have served to bring into operation some 
more powerful agency, whose effects are revealed in the 
production and augmentation of the non-nitrogenous 
constituents. 

If we take the quantity of mineral substances absorbed 
as the measure of their importance for the organic opera- 
tions going forward in the plant, we must assign to sul- 
phuric acid and common salt an influence equal to that 
of any of the others. 

Looking at the quantities of mineral constituents 
severally taken up by the different parts of the plant in 
tlie various stages of growth, we observe the greatest 
disparities. In the second stage, a quantity of potash, 
amounting in the aggregate to 49-29 pounds, was absorbed 
in 35 days ; and of this, the roots were found to contain 
8-02 pounds, equal to one-sixth — the leaves 41-27 pounds, 
equal to five-sixths. The same proportion — namely, 
about five to one —was found to exist between the weight 
of the leaves produced, and that of the roots. 

In the third stage, the weight of the roots produced 
exceeded that of the leaves ; and of the 80 pounds of 
potash absorbed by the plants, 34 pounds, or more than 
one-third, remained in the roots. The same was found to 
be the case with phosphoric acid, and the other mineral 
constituents ; that is to say, they were found distributed 
in varymg proportions, corresponding to the growth and 
increase of the mass of the overground and underground 
organs of the turnip plants, which, in the various stages, 
are hkewise not uniform. 



NITEOGENOUS SUBSTANCES IN TURNIPS. 23 

If we regard the mere increase of the leaves and roots 
in mineral substances, without reference to the total 
amount of them absorbed by the entire plant, it appears 
to be most irregular, and to proceed by ' fits and starts.' 
The plant receives every day nearly the same quantity of 
phosphoric acid, nitrogen, salt, and sulphuric acid, which 
are distributed in the several parts of the plant, leaves, 
or roots, where they are required for use. The chief 
difference observable is in the increase of potash, which 
in the third stage is out of all pro]3ortion greater than 
that of the other mineral constituents. 

It is highly probable that from the raw material — i. e. 
the carbonic acid, water, ammonia, phosphoric acid, 
sulphuric acid, with the cooperation of the alkalis, earths, 
&c. — the chemical process engenders in the plant simply 
a nitrogenous and sulphureous substance, belonging to the 
albumen group, and only one non-nitrogenous substance, 
belonging to the group of hydro-carbons. The former 
retains its character during the period of vegetation ; 
while the non-nitroo-enous substance is converted into a 

o 

tasteless, gum-like body, or into cellulose, or sugar — 
becoming a constituent of the leaves or of the roots, 
according as the organic energy preponderates in the 
overground or underground organs. 

If there is a relation between the phosphoric acid and 
the production of the nitrogenous constituents, the soil 
must contain, in its parts, definite proportions of both 
substances ; and for the cultivation of turnips, the upper 
layers must necessarily be much richer in phosphates 
than the lower. For in the first half of the period of 
vegetation, the branching of the roots is much less 
extensive than at a later period, and the root is in contact 
with a much smaller bulk of earth than afterwards ; 
hence, if the root is to draw from this smaller bulk the 



24 THE PLANT. 

same amount of nourisliment as from the larger, the 
former must contain more of it, in proportion as the 
absorbent root-surface is smaller. 

The ash of all plants in whose organism large quantities 
of amylum, gum, and sugar are produced, is distinguished 
from the ash of other plants by the preponderance of 
potash ; now, if the potash in the sap of the turnip plant 
formed a necessary agent in the formation of sugar and 
the other non-nitrogenous constituents, the quantity of 
that mineral matter absorbed in the third and fourth 
stages of growth is easily explained — because the forma- 
tion of the non-nitrogenous constituents of the root was 
more active in these than in the former stages. 

That the production of the combustible constituents — 
the conversion of the carbonic acid and ammonia into 
non-nitrogenous and azotised substances — stands in a 
definite relation of dependence to the incombustible 
matter found in the ash, is an opinion which no longer 
requires special proof to support it. But the dependence 
is mutual. To say that the reason why the azotised or 
non-nitrogenous products are formed in large proportion 
is because the plant has taken up more phosphoric acid 
or potash, is just as correct as to assert that the plant 
takes up more phosphoric acid or potash because the 
other conditions required for the production of azotised 
or non-nitrogenous substances are found combined in its 
organism. 

To enable a plant to attain its maximum of grow-th, 
the soil must at all times yield, in an available form, the 
whole quantity of each of its constituents ; and, on the 
other hand, the cosmic conditions — heat, moisture, and 
sunhght — must cooperate to transmute the absorbed 
substances into the organs of the plant. If the substances 
that have passed from the soil into the plant cannot be 



DIFFEEENT PERIODS OF GROWTH IN THE TURNIP. 25 

turned to account, from the want of this cooperation, no 
fresh substances are absorbed ; in unfavourable weather, 
the plant does not grow. No more does it grow, even 
though the outward conditions are favourable, if the soil 
contains no proper nourishment. 

In the second half of the period of developement, the 
roots of the turnip plant, having penetrated through the 
arable surface deep into the subsoil, absorb more potash 
than in the preceding stage. If we suppose that the 
absorbing spongioles of the root reach a stratum of soil 
poorer in potash than the upper layer, or not sujfficiently 
rich in that material to yield a daily supply commensm-ate 
with the requirements of the plant, at first, indeed, the 
plant may appear to grow luxuriantly ; yet the prospect 
of an abundant crop will be small, if the supply of the 
raw material is constantly decreasing, instead of enlarging 
wdth the increased size of the organs. 

In the economy of the turnip, the root receives during 
the last month of vegetation nearly one-half of all the 
movable constituents of the leaves ; and this constitutes, 
after the completion of its first year's period of vegetation, 
a store of organisable matter for future use. 

During the spring of the following year the root begins 
to shoot, putting forth a slight leafy top, and a flower- 
stalk several feet high ; with the developement and 
maturing of the seed, the plant dies. The chief bulk of 
the food stored up in the root is applied, in the second 
year or third period, in quite a different direction ; 
though, beyond the mere supply of water, the soil seems 
to take no part in this new act of life. 

All monocarpous plants — that is, all plants which 
flower and produce seed but once — present, like the 
turnip plant, distinct periods of life, as regards the direc- 
tion of organic activity in them. In the first, the plant 



26 THE PLANT. 

produces the organisable matter required in the succeed- 
ing period ; in the latter, that which is requu-ed for the 
final functions of life. But these materials are not always 
stored up in the root, as is the case in the turnip ; in 
the sago-palm they fill the stem ; in the aloe (Agave) they 
collect in the thick fleshy leaves. 

The production of seed is, with many of these plants, 
much less dependent upon any fixed period of time, than 
upon the store of organisable matter collected in them in 
the time preceding. Favourable climatic conditions or 
propitious weather will hasten, while unfavourable cosmic 
conditions will retard, its production. 

The so-called summer-plants are monocarps which are 
able to gather in a few months the conditions required for 
the production of seed. The oat-plant grows to maturity 
and bears ripe seed in ninety days ; the turnip-rape only 
in the second year of its existence ; the sago-palm in 
sixteen to eighteen years ; the aloe in thu-ty to forty, 
often not till 100 years. (See Appendix B.) 

In many perennial plants, the outer part dies every 
year, while the root lives on. In the monocarpous plants, 
the root dies with the production of the seed. Li these, 
the production of seed is an indispensable, in the peren- 
nial plants more of an accidental, condition of continued 
existence. 

The economy of plants is regulated by laws which 
manifest their operation in the pecuhar faculty of certain 
organs to store up food for future use ; so that alLthe 
external causes which seem to hinder their developement, 
actually contribute in the end to insure their continued 
existence, i. e. their propagation. 

The contents of the roots in perennial grasses and 
asparagus, may, in the different periods of the life of these 
plants, be compared to the farinaceous body or albumen in 



INFLUENCE OF THE LOSS OF LEAVES ON TURNIPS. 27 

the grain of cereals ; with this difference, however, that 
the skin does not become empty, as is the case with the 
latter on germination, but is always re-filled and keeps 
increasing in size. The perennial plant always receives 
more than it expends ; whereas the monocarpous plant 
spends its whole store in forming fruit. 

The fact that the roots of the turnip, in autumn, grow 
at the cost of the constituents of the leaves, readily 
explains the influence which the removal of leaves will 
exercise upon the crop at different stages of growth. 
The removal of a few leaves in August makes no great 
difference to the root, while the removal of leaves at the 
end of September causes the greatest damage to the root- 
crop. Metzler, who made very accurate comparative ex- 
periments upon this point, found that an early cutting of 
the leaves reduced the turnip crop by 7 per cent, only, 
while a late, or a second cutting, reduced it by as much as 
36 per cent. 

If, in the first year, instead of the turnips being removed 
from the field at harvest, the tops were merely cut off and 
the roots were left and ploughed in, the field would, on 
the whole, sustain a loss of soil constituents ; still the roots 
in the soil would retain the greater portion of them. A 
very different relation would arise, if at the end of the 
second year of vegetation the turnip tops were cut off, and 
the stem were removed together with the seed. For, at 
the end of the first year, the root would still retain the 
far larger portion of the azotised and also of the incom- 
bustible constituents, which would thus be left in the soil ; 
but in the second year these materials would be carried 
into the overground part of the plant, and there be used 
for the production of the stem and the seed ; hence, the 
removal of the latter would of course make the soil poorer, 
even though the roots were now left in it. Before the 



28 THE PLANT. 

shooting and flowering, the root was rich in soil con- 
stituents ; after the production of seed, its store of them is 
exhausted. If the plant is cut off and the root left in the 
ground, before flowering, the soil retains the far greater 
portion of the nutritive matter which it had given to the 
plant ; on the contrary, after flowering and the production 
of seed, the root retains only a small residue of these con- 
stituents, and the soil is correspondingly exhausted of 
them. 

As it is with the turnip, so is it with culmiferous plants. 
If they are cut off before flowering, a considerable portion 
of the nutritive substances stored up in them remains in 
the root, which the soil of course loses, if the overground 
plant is removed after the ripening of the seed. 

The experience derived from the cultivation of tobacco 
gives a clear view of the processes in the developement of 
an annual leafy plant. 

In the tobacco plant the overground and the under- 
ground parts grow with perfect equality ; the root gains 
in extent, in the same proportion as the stem lengthens 
and the leaves increase in number and size. There is no 
appearance of sudden changes in the direction of organic 
activity, no shooting, but the phases of hfe in the plant 
follow in steady continuous progression. Even while the 
top of the stem bears ripe seeds, and the lower leaves 
have withered, the side shoots of the plant are often still 
putting forth flower-buds, the seeds of which will ripen at 
a much later period. 

The tobacco plant is remarkable for producing in its 
organism two nitrogenous compounds, of which the one, 
nicotine, contains neither sulphur nor oxygen ; while the 
other, albumen, is identical with the sulphureous and 
oxygenised constituents of the cereals and other alimen- 
tary plants. 



THE TOBACCO PLANT. 29 

The commercial value of tobacco leaves is in an inverse 
ratio to the amount of albumen which they contain, that 
sort of tobacco being most highly esteemed by smokers 
which contains the least albumen ; for the latter ingredient, 
in the burning of the dry leaves, emits on carbonisation a 
most disagreeable smell of burnt horn shavings. The 
leaves rich in albumen contain, as a rule, more nicotine 
than those which are poor in albumen ; they give the 
strongest kinds of tobacco, many of which cannot be 
smoked unmixed. 

The tobacco leaves cultivated in France and Germany 
are manufactured either into smoking tobacco, or into 
snujEF. For the fabrication of snuff, leaves* which are rich 
in albumen and nicotine are preferred to those containing 
a smaller amount of those ingredients. The leaves in- 
tended for snuff are, either when still entire or after being 
ground to powder, subjected to a kind of fermentation, 
which takes place pretty speedily, with evolution of heat, 
if they are kept moistened with water. From the putre- 
faction of the albumen there arises a considerable quantity 
of ammonia, which is a principal ingredient of German 
snuff, and is also occasionally increased by the manufac- 
turers, by moistening with carbonate of ammonia or caustic 
ammonia, to suit the taste of consumers. 

The leaves intended for smoking are also improved in 
quality by a slight process of fermentation, which serves 
to diminish the quantity of albumen in them. 

These preliminary remarks will help to explain the 
different methods of cultivating tobacco. 

The size of the leaf in length and breadth, its light or 
dark colour, the height of the stem, the amount of pro- 
duce, and the greater or less proportion of albumen and 
nicotine, all depend very essentially upon the manuring of 
the plant. 



30 THE PLANT. 

The plant succeeds best, in Europe, on light, sandy, 
humose, loamy, or marly soils. The strongest kinds, 
richest in albumen and nicotine, are grown on vkgin land, 
and on heavy clay soil manured with bone-dust, shavings 
and clippings of horns and claws, blood, bristles, human 
excrements, oilcake, and liquid manure. 

In Havannah, tobacco is grown on virgin soil, on 
cleared forest lands, which are often burnt first, as is done 
in Virginia. The best qualities (the poorest in albumen) 
are yielded in the third year of cultivation. 

From this it would appear, that animal manure 
abounding in nitrogen (ammonia) favours the production 
of nitrogenous "constituents ; but the soil, on the other 
hand, which is poor in ammonia, and probably contains 
the nitrogen in the. form of nitric acid, produces leaves 
containing much less albumen and nicotine. 

The effect of removing the tobacco plant from the 
rearing beds to the field is very striking. Transplanted 
into the new soil, the young tobacco plant proceeds in 
the first instance, hke seed in the process of germination, 
to produce roots ; the leaves already formed wither on 
transplantation, and thek movable constituents, together 
with the store of organisable matter collected in the 
roots, are apphed to the production of numerous branch 
radicles. A second transplantation has a still more 
favourable effect upon the underground organs of absorp- 
tion. 

As the direction of the organic operations in summer- 
plants is entirely turned to the formation of seed, and as 
this consumes the materials which give activity to the 
roots and leaves, the tobacco planter breaks out, when 
the plant has put forth six to ten leaves, the heart of the 
middle stem, on which the flowers and seed ca23sules 
grow. Stripped thus of the crown, the whole vigour of the 



CULTIVATION OF TOBACCO. 31 

plant is now directed to the buds between the leaves and 
stem, and these put forth side-shoots which are treated 
like the principal stem, that is to say, they are either 
broken away, or simply cracked by twisting. Thus the 
leaves retain the organisable matter subsequently produced, 
and increase in mass and size, while the amount of water 
in them diminishes. By the middle of September, the 
leaves lose their green colour and are spotted with yellow 
blotches, imparting a marbled look ; they become parch- 
ment-hke, feel dry to the touch, get flaccid, with the 
ends drooping to the ground, and, when arrived at full 
maturity, are viscous, clammy, and readily come off 
the stem. 

This treatment is variously modified, according to the 
several varieties of tobacco, and the different countries in 
which it is grown. The so-called common Enghsh 
tobacco, which is particularly rich in nicotine, is often 
allowed by planters to run to seed, in order to effect a 
separation of the nitrogenous constituents, the albumen 
forsaking the leaves and lodging in the seed. 

In the young shoots, buds, and generally in all parts in 
which the production of cells is most actively carried on, 
the sulphureous and nitrogenous constituents (albumen) 
accumulate, and thus the younger leaves are always 
richer in these substances than the older. The leaves 
nearest the ground (sand-leaves) give a milder, the upper 
leaves a stronger, tobacco. In those varieties which are 
not particularly rich in nicotine and albumen, the sand- 
leaves are of much less value than the upper leaves. 
A mild tobacco always means a tobacco poor in narcotic 
constituents. 

The course pursued by the European tobacco planter, 
who lays a superabundance of animal manure upon his 
fields, is the exact reverse of that adopted by the 



32 THE PLANT. 

American planter, who cultivates his plants upon a field 
that has never been manured. The one seeks to reduce 
or dilute the narcotic, sulphureous, and nitrogenous con- 
stituents of the leaves; the other to concentrate them. 
Accordingly, the American planter breaks the lower leaves 
in their full vigour, when the plant has attained to half- 
growth ; the European planter attaches the greatest value 
to the fully-developed upper leaves. 

As the tobacco plant, like all annuals, only yields up 
its whole store of organisable matter at the ripening of 
the seeds, the stem does not die after the loss of the 
leaves ; but the materials still remaining in it and in the 
roots cause the stem to send forth fresh shoots, and fre- 
quently even leaves, though small-sized ones. In the 
West Indies, Maryland, and Virginia, before the gathering 
of the leaves, the stems are notched immediately above 
the ground, so that they lean over without being severed 
from the root. In warm weather, the water in the leaves 
evaporates, and a motion of the sap ensues from the stems 
and roots towards the leaves, in which the sap is thus 
concentrated as the plant withers. The tobacco planters 
on the Ehine have found that a superior tobacco, poorer 
in albumen and nicotine, is produced if, instead of breaking 
the leaves off in the field, the plant with the leaves on it 
is cut down just above the ground, and hung up to dry 
with the top downwards. The stem wiU, under these 
circumstances, continue to vegetate for a time, sending 
forth small shoots which gradually turn in an upward 
direction and put forth flower-buds. In these flower-buds 
the sulphureous and nitrogenous constituents are collected 
from the leaves, which lose these ingredients in the same 
proportion, and are thereby improved in quality. 

Of the plants cultivated for the sake of their seed, 
wheat liolds the chief place. 



MODE OF GEOWTH OF WINTEE WHEAT. 33 

Winter wheat is in its developement extremely like a 
biennial plant. Li the biennial turnip we see that with 
the first leaves a corresponding number of root-fibres are 
produced ; and that after the formation of the leaf-top, 
the root begins to expand greatly in size and extent, 
immediately after which the flower and seed-stalk shoots 
forth. 

Very soon after winter-wheat is sown, the young plant 
puts forth the first leaves, which in the course of winter 
and the early months of spring increase to a tuft ; to all 
appearance the vegetation of the plant seems to cease for 
weeks and months. When warm weather comes, the 
plant puts forth a soft stem, several feet high, furnished 
with leaves, and bearing at the top an ear set with flower- 
buds in which, after flowering, the seeds are formed. As 
the seed is developed, the leaves from the bottom upwards 
turn yellow, and die with the stem as the seed ripens. 

It cannot be doubted that while the growth of the 
plant appears to have ceased before the time of shooting, 
the over and under ground organs are in constant activity ; 
food is incessantly absorbed, which, however, is but par- 
tially employed to increase the mass of leaves, but not 
to form the stem. There is, therefore, every reason to 
beheve that the far larger portion of the organisable 
matter produced in the leaves during this period goes to 
the roots, and that this store is afterwards applied to the 
formation of the stalk. On the approach of warmer 
weather all the operations of life in cereal plants are 
quickened, and the quantity of food daily absorbed and 
worked up increases with the extent of the absorbing and 
elaborating organs. In spring many of the older leaves 
and of the root-fibres die in the portions of the soil 
exhausted by them ; the root-tops send forth new buds, 
and with every new bud new rootlets, until the stalk- 

D 



34 THE PLANT. 

joints have attained a certain length. From this time 
forward to tlie end of. the period of vegetation, both the 
food absorbed by the plant, and the movable part of the 
materials formed in the leaves, stem, and root, go to form 
flowers and seeds. 

The observations of Schubart show that the roots of 
cereal plants, in the first period of vegetation, increase 
much more than the leaves. Schubart found that rye 
plants, which, six weeks after sowing, presented leaves 
5 inches long, had meanwhile produced roots 2 feet in 
leno'th. 

The vigour with which cereal plants send forth their 
stalks and side-shoots corresponds to the developement of 
the root. Schubart found as many as eleven side-shoots 
in rye plants, with roots 3 to 4 feet long ; in others, where 
the roots measured If to 2^ feet, he found only one or 
two ; and in some, where the roots were but 1^ foot, no 
side-shoots at all. 

The action of a low temperature in autumn and winter, 
which puts a certain limit to the activity of the outer 
organs, without altogether suppressing it, is essential to 
the vigorous thriving of winter corn. It is a most 
favourable condition for future developement, if the tem- 
perature of the air is below that of the soil, so as to retard 
for several months the developement of the outer plant. 

Hence a very mild autumn or winter operates unfavour- 
ably upon the future crop, as the higher temperature en- 
courages the developement of the principal stalk before the 
proper time, which shoots up thin, and consumes the food 
which should have served to form buds and new roots, or 
to increase the store of organisable matter in the roots. 
Thus stunted in its developement, the root supplies less food 
to the plant in spring, as it takes up and gives out less in 
proportion to its smaller absorbent surface and more 



DIFPEEENT STAGES OF GROWTH OF THE OAT-PLANT. 35 

limited supply stored up in it ; and it retains the same 
feeble character in the succeeding periods of vegetation. 
The agriculturist endeavours to meet the difficulty by 
grazing dowii or cutting these feeble plants ; the formation 
of buds and roots hereupon begins anew, and if the ex- 
ternal conditions are favourable, and the plant has time to 
fill the root with a fresh store of organisable matter, the 
normal conditions of growth are, in the agricultural sense, 
restored. Summer corn maintains, in the several periods 
of its developement, the same character as winter corn ; 
only these periods are of much shorter duration. 

Ahrend's study of the oat-plant in its several stages of 
growth is instructive in this respect. He determined the 
increase in combustible and incombustible constituents 
during the following periods : fi"om germination to the be- 
ginning of shooting (end of the first stage, 18th June) ; 
from this time to shortly before the end of shooting (second 
stage, 30th June) ; immediately after flowering (third stage, 
10th July) ; the commencement of ripening (fourth stage, 
21st July) ; finally, to perfect maturity (fifth stage, 31st 
July). On the 18th June the plants were on an average 
31 centimeters high (1^ inch), the three lower leaves 
were nearly expanded, the two upper leaves were still 
folded up. Of the stalk-joints the three lower alone had 
an appreciable length (1, 2, and 3 centimeters), the three 
upper had but a rudimentary existence. Twelve days 
after (on the 30th June) the plant had attained double the 
height (63 centimeters) ; and ten days after this again, on 
the 10th July, after flowering, it had reached 84 centi- 
meters. 

1,000 plants respectively produce in grammes : — 



36 



THE PLANT. 





Esainiuecl on 


ISth June. 


30th June. 


lOth Jvly. 


21st July. 


31st July. 




I. stage. 


II. stage. 


III. stage. 


IV. stage. 


V. stage. 


Constituents 


In 49 days, 


In 12 days, 


In 10 days, 


In 11 days, 


In 11 days. 




before 


stalks full 


flowering. 


formation of 


ripening. 




shooting. 


grown. 




seed. 






CJ-rammes 


Grammes 


Grammes 


Grammes 


Grammes 


Combustible . 


419 


873 


475 


435 


128 


Incombustible 


36-6 


33-48 


30-33 


20-34 


7-18 






In one day. 






Combustible . 


8-551 


72-75 


47-50 


39-45 


12-8 


Proportion . 


1 


8-5 


5-5 


4-6 


1-5 


Incombustible 


0747 


2-79 


3-03 


1-849 


0-318 


Proportion . 


1 


3-73 


4-06 


2-47 


0-96 



In looking at these figures we must remember that 
Ahrends could only determine what the overground part 
of the plant had received from the root, not, as Anderson 
in the case of the turnip, what the whole plant had derived 
from the soil. The great disparity in the increase of com- 
bustible and incombustible substances evidently depends 
rather upon the unequal distribution of the materials ab- 
sorbed, than upon any disparity in the quantity derived 
from the soil. The whole period of developement comprised 
about 92 days, and we see that for more than the first 
half (49 days) the plant remains stationary at an apparently 
low stage of growth, the fohage alone being developed, 
and that not fully. In the next 12 days, from the 18th 
to the 30th June, the plant gains double the weight of 
incombustible constituents, and grows twice as high as in 
the 49 days preceding ; and within this short time, the 
overground parts absorb nearly the same quantity of in- 
combustible constituents as they had previously taken up. 
In fact, the plant takes up 8^ times the quantity of com- 
bustible matter, and o| times more of ash constituents on 
one day of shooting, than upon one of the 49 previous 
days. 

We cannot suppose it at aU likely that the external 
conditions of nutrition, the supply of food by the atmo- 



GROWTH OF THE OAT-PLANT. 



37 



sphere and from the ground, or the absorptive power of 
the plant, should alter and increase, by fits and starts, from 
one day to another. We are led rather to assume that 
the oat-plant is subject in its developement to the same 
law which we have observed in the case of the turnip, and 
that therefore, in the second half of the first stage of 
growth, the activity of the leaves was principally directed 
to the production of organisable matter, to be stored up 
in the root for the shooting stage, and then supplied to 
the overground organs of the plant. The heightened as- 
similative or working power of the plant, consequent upon 
the higher temperature and brighter sunshine of summer, 
was attended by a proportionate increase in the supply of 
food ; but the relative proportion of the soil constituents 
remained much the same as in the turnip plant. 

If we compare the respective quantities of potash, phos- 
phoric acid, and nitrogen, which the overground parts of 
the oat-plant have received from the root and the soil, in 
the several stages of growth, i. e. to the commencement of 
flowering, thence to incipient ripening, and finally to ma- 
tiuity, we find that 1,000 plants have received : — 



Potash .... 

Nitrogen 

Pliosplioric acid 


In the I. and II. 

stages, 61 days. 


In the I. and II. 
stages, 21 days. 


In the V. stage, 
10 days. 


Grammes 
34-11 
25-0 
5-99 


Grammes 
13-2 
24-9 
6-94 


Grammes 
0-0 
5-4 
1-33 



These proportions show that the daily increase of potash 
in the overground parts of the oat-plant was pretty nearly 
the same in the 21 days of the 3rd and 4th stages, as in 
the 61 days of the 1st and 2nd. But for the phosphoric 
acid and the nitrogen a very different result is obtained ; 
we find that the quantity of these two ingredients whicJi 
passed into the stalk, the ear, and the leaves, amounted 



38 THE PLANT. 

ill the 21 days of tlie 3rd and 4th stages to as much as in 
the 61 days of the 1st and 2nd stages : in other words, 
the overground organs of the plant gained of these two 
ingredients, in the flowering and ripening time, three times 
as much each day as in the preceding period. 

Of the turnip-plant we know with tolerable certainty, 
that from the time when it sends forth a flower-stalk, the 
constituents of the stalk, as also those of the flowers and 
the seeds, are for the most part stored up in the root, and 
are supplied therefrom. It is liighly probable that the 
corn-plant is. similarly circumstanced, and that from the 
flowering to the end of life it is fed, though not exclu- 
sively, by the root, which from the flowering time gives 
out what it had stored up in the preceding period. 

Knop observed that Indian corn plants in flower, taken 
out of the ground and placed with their roots simply in 
water, produced ears with ripe seeds ; which proves that 
the materials serving for the production of seed were 
already present in the plant at the time of flowering. 

It is an established fact that a corn-plant, if cut ofl" 
before flowering, relapses into that lower stage of vege- 
tation of a perennial plant, in which the root receives 
more organisable matter than it parts with.* 

The proportions of incombustible constituents and of 
nitrogen severally required by oats and turnips, are 
remarkably diflerent, both in the aggregate and duruig 
the various stages of growth. The facts established by 
Anderson for the turnip, and by Ahrends for the oat, are 
indeed not sufficiently numerous to warrant us in deducing 

* Buckmaun (' Joiirn. of the Eoj^al Agric. Soc.') soAved wheat on 
a field in autumn 1849, which was continually cut down in 1850, so 
that the plants Avere never alloAved to come to floAver : they AA^ere left 
in dtiring the Avinter 1850-51, and yielded an excellent crop in the 
year 1851. 



GROWTH OF TUENIPS AND OATS COMPAEED. 39 

any positive law of growth for those two plants : still a 
few inferences may easily be drawn from them. The 
quantities of phosphoric acid and nitrogen in the turnip 
are, at the end of the first year of vegetation, nearly in 
the proportion of 1 : 1 ; in oats, on the contrary, of 1 : 4. 
The oat-plant requires to the same quantity of phosphoric 
acid four times as much nitrogen as the turnip ; and the 
latter to the same quantity of nitrogen four times as much 
phosphoric acid. 

If the developement of the oat-plant takes a similar . 
course to that of the turnip, the former must have accu- 
mulated in its underground organs before the time of 
shooting a store of organisable matter, similar to that laid 
up by the turnip at the close of the first year of vege- 
tation. The mass of organic substances accumulating in 
these plants before the developement of the flower-stalk is 
manifestly much larger in the turnip than in the oat- 
plant. The former receives from the soil much more 
phosphoric acid and nitrogen ; but the turnip had 122 
days, the oat-plant only 50 days, up to the period of 
shooting for extracting these nutritive substances from 
the ground. Now if the turnips and oats growing on a 
hectare (2^ acres) of land had daily received an equal 
amount of them, then, all other circumstances being the 
same, the quantity of nutritive substances absorbed would 
be proportionate to the time of absorption. In this 
respect the nature of the root makes a great difference, 
according to the extent of absorbent root-surface. The 
larger root-surfaCe is in contact with more earthy par- 
ticles, and can during the same time extract more nutritive 
substances than the smaller. The mass of vegetable 
substance produced, and especially the quantity of non- 
nitrogenous and azotised materials, depend upon the 
nature of the plants. If the absorbent root-surface of the 



40 THE PLANT, 

oat-plant were 2-45 times greater than that of the turnip, 
the former would, under hke circumstances, take up daily 
2-45 times as much food as the latter, i.e. the oat-plant 
would absorb in 50 days as much as the turnip in 122 
days. Thus in equal times the power of two plants to 
absorb food is in proportion to their absorbent root- 
surface. 

The time of vegetation occupied by the turnip-plant 
comprises, in the first year, 120 to 122 days, and termi- 
nates at the end of July in the next year with the produc- 
tion of seed. If we take the whole time of vegetation of 
the turnip-plant at 244 days, and suppose the time of 
vegetation of the oat-plant extended from 93 or 95 to 
244 days, we find that this would give sufficient time for 
growing two oat crops, and advancing a third half way to 
maturity ; and a careful investigation might perhaps reveal 
that the quantity of sulphureous and nitrogenous consti- 
tuents produced in the oat-plant is not less than that 
obtained in turnip-plants from an equal area of ground. 

In the grains of the cereals tlie quantity of the sulphur- 
eous and nitrogenous constituents is to that of the non- 
nitrogenous (the quantity of the blood-making substances 
to the amylum), as 1 : 4 or 5 ; in the roots of turnips, or 
in the tubers of potatoes, as 1 : 8 or 10. In the latter, 
therefore, the quantity of the non-nitrogenous constituents 
is in proportion to the other constituents much greater. 

When at a certain temperature the organic process of 
germination begins in a grain of wheat, the embryo first 
sends down a number of rootlets, while the plumule rises 
upward in the form of a short stem, with two or three 
complete leaves. Simultaneously with the changes taking 
place in the embryo, the constituents of the farinaceous 
body (albumen) become fluid ; the amylum is converted 
first into a substance resembling gum, then into sugar, 



FIRST GROWTH OF A GRAIN" OF WHEAT. 41 

while the ghiten changes into albumen, and both together 
form protoplastem (Naegeli's organic food elements), or the 
food of the cell. The fluidity of the new body enables 
it to find its way to the places where the formation of 
cells is going on. The amylum supplies the elements 
required to form the outer wall of the cell ; the nitro- 
genous matter constitutes a principal ingredient of the 
cell contents. Simultaneously with the roots and leaves, 
smaU leaf-buds arise upwards on the stem-joint, and small 
root-buds appear at the basis of the roots. 

In the protoplastem of the wheat-plant the non-nitro- 
genous matter exceeds the azotised matter as five to one. 

Except water and oxygen, no substance from without 
takes any part in these processes. What the seed loses in 
carbon by the formation of carbonic acid in germination 
is afterwards recovered almost entirely by the young 
plant. 

The plant developed under these circumstances barely 
increases in substance to any appreciable degree, even 
though it may continue vegetating for weeks. The organs 
developed from a grain of wheat weigh all together, when 
dried, no more than the gram did before germination. 
The relative proportion of the non-nitrogenous and 
azotised substances in them is almost the same as in the 
farinaceous body, the constituents of which have in reahty 
merely assumed other forms. The leaves, roots, stem, 
leaf-buds and root-buds collectively represent the con- 
stituent parts of the seed, transformed into organs and 
apparatus now endued with the power of performing 
certain operations which serve to carry on a chemical 
process, whereby external inorganic substances, with the 
cooperation of sunhght, are converted into products analo- 
gous in all their properties to the materials from which 
these organs themselves arose. 



42 THE PLANT. 

The organic process of cell-formation presupposes the 
presence of the protoplasm, and is independent of the 
chemical process by which the latter is generated ; but 
this chemical process is indispensable to the continuance 
of the cell-formation. 

In a young plant which has been developed in pure 
water alone, the chemical process must soon come to an 
end for want of the necessary external conditions. The 
leaves and roots in this case can do no work as formative 
organs. In the absence of food they generate no products 
upon which the continued existence of the plant depends. 
When they have arrived at a certain state of develope- 
ment, the cell-formation ceases in themselves, although it 
is still continued in the new root-buds and leaf-buds. The 
latter stand to the movable contents of the previously 
existing leaves and roots in the same relation as the 
embryo of the wheat-seed to the . farinaceous body. The 
non-nitrogenous and azotised constituents which represent 
the working capital of the existing roots and leaves are 
transformed as these die into new organs, and new leaves 
are developed at the expense of the constituents of the 
old ones. But these processes are of short duration ; 
after a certain number of days the young plant dies. 
The more immediate external cause of its short duration 
is the want of food ; but another internal cause is the 
conversion of the non-nitrogenous soluble substances into 
cellulose or woody tissue, whereby it loses mobility. 
With the diminution of this soluble substance the most 
essential condition of cell-formation is impaired : when 
the whole has been consumed, the process comes to an 
end. The withered leaves, when burnt, leave behind a 
certain quantity of ash, showing that they retain some 
mineral matter ; there remains in them also a snial] 
portion of nitrogenous substance. 



FUJN^CTIOlSr OF THE NITROGENOUS MATTER OF SEEDS. 43 

The most remarkable thing in this developement is the 
part performed by the nitrogenous matter of the seed, 
which becomes a constituent element of the root-fibres, 
stems, and leaves, where its agency serves to bring about 
the formation of cells. After the death of the first 
leaves, it becomes a constituent of the new ones, per- 
forming in them the same part over again, so long as 
there remains material for ceh-formation. But the nitro- 
genous matter itself is not in reahty worked up in the 
plant, and forms no actual tissue or component part of 
the cell. 

The experiments of Boussingault on the growth of 
plants, in the absence of all nitrogenous food ('Annal. de 
Chim. et de Phys.,' ser. iii., xliii., p. 149), though under- 
taken for a different purpose, are well adapted to remove 
all doubt about the very important power possessed by 
the nitrogenous matter just now alluded to, viz. of main- 
taining the vital process in the plant, even where the 
mass of the plant itself receives no increase. 

In these experiments lupines, beans, oats, wheat, and 
cresses were sown in pure pumice-stone dust, washed 
and burnt, with which was mixed a certain quantity of 
ash from stable-manure and from seeds similar to those 
sown. The plants were grown partly under glass bells, 
with a constantly-renewed supply of air containing 
carbonic acid. The air supplied, and the water used 
for the plants, were most carefully freed from ammonia. 
The results of these experiments were as foUows : — 
In an experiment where the plants were grown under a 
glass beU, 4*780 grammes of seeds (lupines, beans, and 
cresses), containing 0*227 gramme of nitrogen, gave 
16 "6 grammes of dried plants; adding the amount of 
nitrogen in the soil, 0*224 gramme of that element was 
recovered. In an"Sther experiment, where the plants 



44 THE PLANT. 

were grown in free atmospheric air, with the exchision, 
however, of dew and rain, 4*995 grammes of seeds 
(lupines, beans, oats, wheat, and cresses) gave 18-73 
grammes of dried plants. The seeds contained 0*2307 
gramme of nitrogen ; the plants and soil, 0*2499 
gramme. In the first series of experiments, all elements 
of food were supplied to the plants, except nitrogen ; 
the chief conditions required to form unazotised matter 
were given, but those required to form azotised matter 
were altogether excluded. 

The growth of a wheat plant in pure water and 
atmospheric air is unattended with any increase of 
weight. The normal seed-corn contains a certain 
quantity of potash, magnesia, and hme, which are 
required internally for the organic formative process ; 
but it has no excess of these mineral substances that 
could serve to effect the chemical process of a new pro- 
duction of protoplasm. Where the mineral substances 
are excluded, the organs will absorb water, but neither 
carbonic acid nor ammonia ; at all events, these two 
latter substances, even though they be introduced into 
the plant by means of the water, exert no influence upon 
the internal process ; they suffer no decomposition, and 
no vegetable matter is formed from their elements. 

In Boussingault's experiments, the action of the mineral 
substances supplied is unmistakable. The weight of the 
plants produced was nearly 3^ times greater than that of 
the seeds sown : but the quantity of nitrogenous matter 
was the same as in the seeds. Hence we have a clear 
production of non-nitrogenous substance 2J times more 
than the original weight of the seeds. A simple calcula- 
tion shows that the nitrogen in the seed has, under these 
circumstances, caused the generation of 56 times its own 
weight of unazotised matter ; or, what comes to the same 



COUESE OF VEGETATIOlSr IN PLANTS. 45 

thing (taking tlie amount of carbon in the latter at 44 per 
cent, only), the decomposition of 90 times its own weight 
ot carbonic acid. 

The course of vegetation in these plants throws sufficient 
light upon the processes going on in their organism ; in 
the first days their developement was vigorous, afterwards 
languid. The first-formed leaves withered after a time, 
and partly dropped ofi", fresh leaves being developed in 
their stead, which went on in the same way ; and the 
vegetation seemed to reach a point where the newly 
developed parts existed at the expense of the decaying 
portions. A French bean, weighing 0-755 gramme, 
planted on the 10th May, had by the oOth July deve- 
loped 17 leaves, of which the first 11 were then dead 
and gone. The plant flowered, and on the 22nd August, 
when nearly all the leaves had dropped off, produced a 
single small bean, which weighed 4 centigrammes, the 
-Jyth part of the weight of the seed-bean. The entire 
crop weighed 2*24 grammes, very nearly three times as 
much as the seed-bean. Li the case of a rye-plant it was 
very clearly observed how the unfolding of every fresh leaf 
was attended with the death of one of the old leaves. 

In the second series of experiments, the plants had 
absorbed (from the air) 1'92 miUigramme of nitrogen, 
and produced 0-830 gramme more vegetable substance, 
giving 43 milligrammes of unazotised matter for every 
milhgramme of nitrogen. 

The difference in the developement of a plant in pm^e 
Avater from that of one grown, as in Boussingault's ex- 
periments, in a soil supplying the incombustible consti- 
tuents of food, is clear and unequivocal. The organs 
first formed received in both cases their elements from 
the seed ; in both, a certain quantity of mineral substances 
and also of soluble unazotised matter was consumed to 



46 THE PLANT. 

form cellulose in the leaves, roots, and stems ; and the 
proportion of the unazotised to the nitrogenous matter 
was altered. In the plant growing in water, there was a 
constant decrease of unazotised matter ; while in the 
other a certain quantity of that substance was generated 
anew. JSTothing can be more certain than that in Bous- 
singault's experiments, the first-formed leaves acquired by 
the supply of mineral substances the faculty of absorbing 
and decomposing carbonic acid, a power not possessed by 
the plant developed in pure water ; and that as much 
soluble unazotised substance was reproduced as had been 
consumed in the formation of the leaves and roots, by the 
conversion into cellulose of the store originally present. 

In the movable constituents of the plant, the relative 
proportion between the unazotised and the azotised seed 
constituents was manifestly restored pretty nearly as it 
existed in the seed ; both matters passed through the 
stem into every new formed leaf-bud, and took part in the 
developement of new leaves, by whose operation the con- 
sumption of unazotised matter was always made good 
again within a certain limit, so that the same process 
could be repeated again and again for months. In every 
one of the dead leaves (and root fibres) a certain quantity 
of the azotised substance remained behind, and in the last 
period of vegetation the floating remainder of this sub- 
stance was collected in the pod and the seeds. 

The supply of mineral substances had served to effect 
the continuance of the chemical process, and caused the 
production of imazotised substances. By the presence of 
these mineral bodies, and by the cooperation of the azo- 
tised matters, new material was engendered from carbonic 
acid to form the cell- walls, and the term of life was pro- 
longed to its proper limit. The most remarkable point 
is, that a quantity, comparatively so small, of azotised 



FUNCTION OP AZOTISED MATTER IN PERENNIALS. 47 

substance derived from tlie seed, should so long be able 
to perform its assigned functions, apparently without suf- 
fering any alteration ; so that in the body of the living 
plant, made to produce and collect it, it would seem to 
possess a kind of indestructibility. 

If we consider, that, in the cited experiment with the 
French bean, a great part of the additional unazotised 
substances which were produced fell away in the dying 
leaves from the body of the plant, it will be seen that the 
supply of mineral substances was of no use to the bean- 
plant in the absence of nitrogenous food. 

Lastly, it is quite intelligible that the amount of azo- 
tised matter contained in a bean might perhaps suffice to 
sustain for years the vegetation of one of the conifers 
with persistent leaves, and to produce many hundred — 
perhaps many thousand — times its own weight of woody 
substance ; and that such a plant upon a barren soil alto- 
gether unsuited for other plants, might thrive with a very 
sparing supply of nitrogenous food, if the soil contained a 
proper store of those mineral substances which are indis- 
pensable for the generation of unazotised matter. 

The growth of a plant essentially consists in the en- 
largement and multiplication of the organs of nutrition, 
i.e. the leaves and roots. The enlargement of the first, 
or the production of a second leaf or root fibre, requires 
the same conditions as the production of the first. The 
analysis of the seeds teaches us with tolerable certainty 
what these conditions are. In the normal conditions of 
nutrition, the first roots and leaves, whos.e elements were 
supplied by the seed, produce from certain mineral sub- 
stances organic compounds, which become parts and 
constituents of themselves, or constituents of fresh leaves 
and roots, consisting of the same elements and having the 
identical properties of the first, i. e. they possess the same 



48 THE PLANT. 

power to transform inorganic nutritive substances into 
organic formative materials. 

It is quite clear that the enlargement of the first leaves 
and roots and the production of new ones, must have 
required azotised and unazotised substances in the same 
proj^ortion as in the seed, which makes it probable that 
the organic operations of the plant under the dominion of 
sunlight uniformly produce in all periods of growth the 
same materials, i.e. the constituent elements of the seed, 
which serve to build up the plant, bemg formed into 
leaves, stems, and root-fibres, or finally into seed. The 
soluble constituents of a bud, a tuber, or the root of a 
perennial plant, are identical with the seed constitu- 
ents. The cereal plant produces azotised and unazotised 
substances in the same proportion as in the albumen 
(farinaceous body). The potato plant produces the con- 
stituents of the tuber, which are formed into leaves and 
branches or roots ; or, if the external conditions are no 
longer favourable to the formation of leaves and roots, 
accumulate again in the underground stem, to form new 
tubers.* 

While the growth of the plant continues, the first as 
well as the last leaves and roots, will, with a proper 
supply of food, maintain their existence, since they repro- 
duce out of the nutriment supphed to them the identical 
constituents from which they themselves arose. The 

* Boiissingault has observed that even seeds weighhig two or three 
milligrammes, sown in an absolutely sterile soil, will produce plants 
in which all the organs are develojaed, but their weight, after months, 
does not amount to much more than that of the original seed, even if 
they vegetate in the open air ; and the result is more marked if they grow 
in a confined atmosphere. The plants remain delicate, and appear 
reduced in all dimensions ; they may, however, grow, flower, and even 
bear seed, which only requires a fertile soil to produce again a plant of 
the natural size. (' Compt. rend.' t. xliv. p. 940.) 



CONDITIONS FOE FOEMING FLOWEE AND SEED. 49 

excess of these, which they do not requu-e for their own 
enlargement, goes to those parts of the plant where the 
motion of the fluids or the cell-formation is most active, 
— viz., to the roots, the leaf-buds, or the extreme points 
of the roots and shoots ; and, finally, as in the case of 
summer plants, to the organs of seed-formation, wliich at 
the ripening of the seed absorb most of the movable 
seed-constituents existing in the plant. 

The supply of the incombustible elements of food led 
to the formation of unazotised matter, a portion of which 
was used to form woody tissue, whilst another portion 
remained available for the same purpose. The supply of 
nitrogenous food caused a corresponding production of 
nitrogenous matter, so that the protoplasm was con- 
stantly renewed, and, so long as the chemical process 
lasted, was increased. 

To enable a plant to flower and bear seed, it would 
appear necessary in the case of many plants that the 
activity of the leaves and roots should reach a period of 
rest. It is only after this that the process of cell-forma- 
tion seems to gain the ascendancy in a new direction ; 
and the constructive materials being no longer required 
for the formation of new leaves and roots, are used to 
form the flower and the seed. In many plants the want 
of rain, and the consequent deficiency of incombustible 
nutritive substances, will restrain the formation of leaves 
and hasten the flowering. Dry, cool weather favours the 
production of seed. In warm and moist chmates the 
cereals sown in summer bear little or no seed ; and on a 
soil poor in ammonia the root-plants more readily flower 
and bear seed than on a soil rich in that substance. 

If the normal processes of vegetation require a definite 
proportion of unazotised and azotised materials in the 
protoplasm which is formed in the plant, it is evident 

E 



50 THE PLANT. 

that the want or excess of the mineral substances indis- 
pensable for the production of those matters must exercise 
a very decided influence upon the growth of the plant, 
and upon the formation of the leaves, roots, and seed. 
Want of azotised and excess of fixed nutritive substances 
would lead to the formation of unazotised materials in 
preponderating quantity ; but when these have assumed 
the form of leaves and roots, they retain a certain amount 
of nitrogenous matter, thereby impairing the seed forma- 
tion, a principal condition of which is an excess of proto- 
plasm. An excess of azotised food, with a deficiency of 
fixed nutritive substances, will be of no use to the plant 
itself, because the latter can for its organic operations 
make use of nitrogenous substances only in proportion as 
they exist in the protoplasm, and the contents of the 
cell are of no value to the plant in the absence of the 
materials required to form the cell-walls. 

In the process of animal fife the organs of the body are 
constructed from the elements of the egg ; the constituent 
parts of such constructed organs are azotised, whereas in 
the plant they contain no nitrogen. All processes of 
vegetative life tend simply to produce the elements of 
the seed. The plant only lives in generating the egg- 
constituents and the egg itself ; the animal only lives by 
destroying these very egg-constituents. 

On one and the same soil equally suited for the turnip 
and the wheat-plant, the former produces for the same 
amount of azotised substance twice as much unazotised 
matter as the latter. It is manifest that if two plants 
produce within the same time different quantities of 
hydrates of carbon (wood, sugar, and amylum), the 
organs of decomposition must be arranged in a manner 
not only to afford adequate room for the carbonic acid 
supplying the carbon, and for the water supplying the 



ABSOEPTION BY THE ROOTS OF PLANTS NOT OSMOTIC. 51 

hydrogen, as well as to present a suitable extent of surface 
to the action of the light, but also' to permit the hberated 
oxygen to escape as promptly as it becomes free. If we 
compare in this respect the leaves of a wheat-plant with 
those of a turnip-plant, we find a striking difference in 
their size, and in the amount of water respectively con- 
tained in them ; and a microscopic examination reveals 
still greater differences. The wheat-plant has erect leaves, 
. which present to the light a much smaller surface than 
the leaves of the turnip-plant, which overshadow the 
ground, preventing the drying of the soil and the exha- 
lation from it of carbonic acid. In the wheat-leaf the 
stomates are equally thick on both sides ; in the turnip- 
leaf they are much more nmiierous, although smaller than 
in the wheat-leaf, and a far greater number of them are 
found on the lower than on the upper side. 

AH the facts known respecting the nutrition of plants 
tend to prove that it is not by a mere osmotic process that 
they absorb their food, but that the roots perform a very 
definite active part in selecting from the amount of food 
presented to them such matters and in such quantities as 
are best suited to the plant. 

The influence of the roots is most manifest in the vege- 
tation of marine and fresh-water plants, whose roots are 
not in contact with the soil. 

These plants receive their incombustible nutritive sub- 
stances from a solution in which these elements are most 
uniformly mixed and diffiised ; and yet a comparative 
analysis of the water and the ash-constituents of these 
plants shows that each species absorbs from the same 
solution different quantities of potash, hme, sihcic acid, 
and phosphoric acid. 

The ash of duckweed was found to contain 22 parts of 
potash to 10 parts of chloride of sodium, whereas the 

E 2 



52 THE PLANT. 

water in whidi the plant had grown contained only 4 
parts of potash to 10 parts of chloride of sodium. In the 
plant the relative proportion of the sulphuric acid to the 
phovsphoric acid was 10 to 14 ; in the water, 10 to 3. 

It is quite the same with marine plants. Sea-water 
contains for 25 or 26 parts of chloride of sodium 1*21 to 
1-35 of chloride of potassium ; but the plants growing in 
it contain more potash than soda. The kelp of the 
Orkney Islands, which consists of the ashes of many 
species of fucus,* contains for 26 per cent, of chloride of 
potassium only 19 per cent, of chloride of sodium. 

Sea-water contains manganese, but in such exceedingly 
small quantity that it would certainly have escaped 
analysis, were it not invariably found among the ash- 
constituents of many marine plants. The ash of Padina 
pavonia (a species of tang) is found to contain of this 
mineral even more than 8 per cent, of the weight of the 
dried plant.f 

By the same power of selection the laminaria withdraw 
from the sea-water in which they grow the iodine com- 
pounds present in it in such exceedingly minute quanti- 
ties. Chloride of potassium and chloride of sodium have 
the same form of crystalhsation, and so many other 
properties in common, that without the aid of chemical 
means we cannot accurately distinguish the one from the 
other. But the plant clearly discriminates between the 

* See Godeclien's analysis of the ash of different sjDecies of fucus. 
(' Annal. d. Chem. tind Pharm.' liv. 351.) 

■]■ To give some idea of the extraordinary power which this plant 
must possess to withdraw the manganese from sea-Avater, I need 
simply state that the quantity of this metal in sea- water is so exceed- 
ingly small, that I coiild find distinct traces of it only by subjecting 
the sesquioxide of iron, obtained from twenty pounds of sea-water, 
to a most searching analysis. (Forchhammer and Poggendoff, xcv. 
p. 84.) 



OSMOSIS AND ABSORPTION BY ROOTS. 53 

two salts, for it separates the one from the other, and for 
every one equivalent of potassium which it absorbs 
leaves behind in the water more than thirty equivalents of 
sodium. Manganese and iron, iodine and chlorine, are 
hkewise isomorphous bodies ; yet the iodine plant sepa- 
rates one equivalent of iodine in sea-water from many 
thousand equivalents of chlorine. 

The known laws of osmosis, and of the diffusion or 
interchange of water and salts through a dead membrane 
or a porous mineral body, give no explanation whatever 
of the action exercised by a living membrane upon salts 
in solution, or how they pass through it into the plant. 
The observations of Graham (' Pliil. Mag.' ser. IV. August 
1850) show that matters capable of exerting a chemical 
action upon animal membranes, such as carbonate of 
potash and caustic potash, causing them to swell and 
gradually decomposing them, facilitate the passage of 
water to an extraordinary degree.* Graham remarks 
that the processes of alteration, decomposition, and new 
formation, which are incessantly taking place in the 
membranes and cells in all parts of the plant, and which 
we have no means of defining or measuring, must entirely 
change the osmotic process : the permeation of mineral 

* The water in the tiibes of liis osmometer rose to 167 millimeters, 
when holding \ jl^m. per cent, of carbonate of potash in solution ; with 
1 per cent, of that salt, it rose to 863 millimeters (38 inches, English). 
In another experiment, the water holding 1 per cent, of sulphate of 
potash in solution, rose to twelve millimeters ; upon the addition of 
1/10 per cent, of carbonate of potash to the solution, it rose to 254- 
264 millimeters ; the same potash solution by itself rose only to 92 
millimeters. The notion of an osmotic equivalent is altogether inad- 
missable, if the membrane is chemically altered. Graham's latest 
investigations on the dialysis of crystalline and amorjohous bodies are 
extremely interesting, and promise to throw considerable light upon 
the processes in the animal organism. 



54 THE PLANT. 

substances through the Hving vegetable membrane must, 
therefore, be governed by very complex laws. 

Land plants act in the same manner with respect to the 
soil in which they grow, as marine plants to sea-water. 
One and the same field presents to the plants growing in 
it, the alkahes, alkaline earths, phosphoric acid, and ammo- 
nia, in absolutely the same form and condition ; but the 
ash of no one species of plant ever shows the same 
relative proportions of component elements as the ash of 
another species. Even the parasitical plants, which draw 
their mineral constituents in a certain state of prepara- 
tion, from other plants on which they live, as the mistletoe 
(Viscum album), do not comport themselves to the latter 
as a graftling to a tree, but absorb from the sap very 
different proportions of mineral constituents ( 'Annal d. 
Chem. und Pharm.' Hv. 363). Now, as the soil is perfectly 
passive in respect to the supply of these materials, there 
must be some agency at work in the plant itself, which 
regulates the absorption according to the requirements of 
each plant. 

The observations made by Hales (see Appendix C.) 
show that the exhalation from the surface of the leaves 
and branches exercises a powerful influence upon the 
motion of the fluids, and upon the absorption of water 
from the soil. If the plant drew its mmeral food from 
a solution moving about in the soil and passing imme- 
diately into the roots, then two plants of different species 
or kind, placed in the same conditions, would receive the 
same mineral substances in the same relative proportions ; 
but, as we have seen, two plants belonging each to a 
different species contain these substances in the most dis- 
similar proportions. 

That a selection takes place in the absorption of food 
by the roots is a fact beyond dispute. 



POWEE OF SELECTION BY EOOTS NOT ABSOLUTE. 55 

111 the case of aquatic plants, which grow under water, 
exhalation is altogether excluded as a possible operating 
cause of the passing of the food into the body of the 
plant. In these plants the absorbent surface must exer- 
cise very unequal powers of attraction upon the different 
materials, which are presented by the solution in the same 
form and in a state of equal mobility ; or, what comes to 
the same thing, the resistance offered to their passage 
through the outermost cellular layers must be very 
dissimilar. The case cannot be different with the roots 
of land-plants, to judge from the unequal proportions of 
the substances severally absorbed by them. 

The power of the roots to preclude the passing of 
certain substances from the soil into the plant is not 
absolute. Forchhammer (Poggend. ' AnnaL' xcv. 90) 
detected exceedingly minute traces of lead, zinc and 
copper in the wood of the beech, birch, and fir ; and tin, 
lead, zinc, and cobalt in that of the oak ; but the fact 
that the outer rind or bark, in particular, is found to con- 
tain metals of this kind in perceptibly larger quantities 
than the wood, clearly points to the accidental nature of 
their presence, and to their taking no essential part in the 
vital processes of the plant. 

How small the quantities of these metals must be 
which the roots of these trees absorb may be judged from 
the fact that hitherto chemical analysis has not been able 
to detect traces of any other metal than manganese and 
iron, in the water of wells, brooks, or springs ; and their 
appearance in these wood-plants, which during the growth 
of half a century or more have absorbed and evaporated 
an immense quantity of water, is the only proof we 
possess, that this water must actually have contained 
these metals in some form or other. 

The observations of De Saussuee, Schlossbebgeb, and 



56 THE PLANT. 

Heeth, show that the roots of land and water plants 
absorb from very dilute saline solutions water and salt 
in proportions entirely different from those in the fluid ; 
in all cases a greater proportion of water, and a less 
quantity of salt. In plants watered with very dilute 
solutions of salts of baryta, Daubeny found no baryta, 
whereas Knop in similar experiments detected this sub- 
stance. The general result of all these experiments is 
that, of themselves, the plants have not the power of 
offering a permanent resistance to the chemical action of 
salts and other inorganic compounds upon the exceedingly 
fine membrane of the root. 

Most land-plants in their natural state in the soil can 
bear no salt solutions, as concentrated as in these experi- 
ments, without sickening and dying ; and even carbonate 
of potash and ammonia, which we certainly know to be 
nutritive substances, act upon many plants as poison, even 
when present in the water which circulates in the ground 
only in sufficient quantity to impart a blue tint to red 
litmus paper. On the other hand, it would be very 
wonderful if the roots of a plant outside the soil, and in 
conditions not suitable to their nature, should, under the 
influence of evaporation, be impenetrable for salt solu- 
tions.* 

* If the long limb of a syphon -shaped tube, filled with water and 
closed with thick pieces of pig or ox bladder tied over both openings, 
is placed in salt-water or oil, and the other limb is exposed to the air, 
the water evaporates in the pores of the bladder with which the short 
limb is closed. By the capillary action of the bladder, the water 
exuding in gaseous form is taken up again on the other side of the 
bladder, and a vacuum is thu.s created in the interior of the tube, 
whence there is an increased pressure upon the surfaces of both 
bladders, which forces the salt-Avater or the oil through the bladder 
into the tube. (' Researches into some of the Causes of the Motion 
of Fluids, by J. v. Leibig. Brunswick : Fr. Viewig& Son. 1848.' — 
p. 67.) A plant in similar conditions is just like a tube closed with 
penetrable porous membranes. 



lEON" NECESSAEY FQR PLANTS. - 57 

Those mineral substances whicli, like iron, are constant 
constituents of all plants, though present only in very 
small proportions, must be regarded very differently from 
those metals which Forchhammer found in woody plants. 

We know the part which iron performs in the animal 
organism, in which it is present in comparatively no larger 
quantities than in the seeds of cereals ; and we are fully 
convinced that, without a certain amount of iron in the 
food of animals, the formation of the blood corpuscles, the 
agents of one of the chief functions of the blood, is im- 
possible. Hence, by the law of dependence, which links 
together the life of animals and plants, we are compelled 
to ascribe to the iron in the plant also an active part in 
its vital functions so material that the absence of that 
metal would endanger the very existence of the plant. 

Hitherto chemistry has attributed a positive part in the 
vital process of plants to those incombustible substances 
only which are common to all, and which differ only in 
the relative proportions in the plants. But should the 
conjecture prove true that iron is a constant constituent of 
chlorophyll and of the leaves of many flowers, it may be 
assumed that other metals, found invariably present in 
certain varieties of plants (as manganese in Pavonia, 
Zostera, Trapa natans, in many ligneous plants, several 
cereals, and in the tea shrub), take part in the vital func- 
tions, and that certain pecuharities depend upon the pre- 
sence of those metals. The ash of Viola calami7iaria, a 
plant which, in the parts about Aix-la-Chapelle, is held so 
strongly indicative of the presence of zinc, that the places 
where it grows are selected for opening new mines in 
search of zinc ore, is found to contain oxide of zinc. 
(Alex. Braun.) 

As chloride of sodium and chloride of potassium cause 
some plants to thrive, so iodide of potassium manifestly 



58 THE PLANT. 

performs a similar part in others ; and if one plant may 
properly be called a chlorine plant, others may with equal 
propriety be termed iodine plants, or manganese plants,* 
(Prince Salm-Horstmar.) 

The diversity in the amount of iodine in different 
varieties of fucus [Goedechens)^ or of alumina in various 
kinds of Lycopodium (Count Laubach), remains, indeed, 
unexplained ; but the power of plants to withdi^aw 
substances like iodine, even in the smallest quantities, 
from the sea water in which they grow, and to accumu- 
late and retain them in their organism, can only be ex- 
plained upon the assumption that these substances have 
entered into combination with certain constituent parts of 
the plants, whereby as long as the plant lives they are 
prevented from returning to the medium from w^hich they 
were taken. f 

It might be supposed that plants become saturated with 
the substances absorbed from the air and from the soil ; 
and that all materials offered by the soil in solution, or 
made soluble by the cooperation of the roots, are absorbed 

* The examination of tlie following water-plants revealed the 
presence of considerable qiiantities of manganese and iron in their ash, 
though the water in which they grew apparently contained no trace 
of manganese: — Victot'ia regia (in the leaf-stalk principally manganese, 
in the leaf iron); Nymplicea coei'ulea^ dentata, lutea; Hych'ocharis 
H'umboldti ; Nelimibiwn asperifolium. (Dr. ZoUer.) 

f With respect to the copper in the grains of wheat and rye, which 
Meier of Copenhagen has shoAvn to be a constant constituent of both 
seeds, Forchhammer (Poggendorif 's '■ Annal.' xc. 92) remarks : — ' It is 
an old and approved practice to steep grains of wheat, intended for 
sowing, in a solution of sulphate of copper. The usual explanation of 
this practice is, that sulphate of copper destroys the sporules of blight 
to which the wheat plant is liable, an explanation which it is not my 
intention to dispute. Still it might also be held, supposing copper to 
be an essential constituent of wheat, that the practice in question 
serves to supply the copper necessary for the vigorous growth of the 
plant.' 



PASSAGE OP MATTERS INTO THE ROOTS. /»9 

without distinction. Upon this assumption, only that 
substance in the plant could of course pass into it from 
without, which is withdrawn from the solution within 
for a formative purpose. 

The investigations made by Schultz-Fleeth show that 
Nymphoea alba and Arundo phragmites absorb from the 
same soil and water, the former nearly 13 per cent., the 
latter 4*7 per cent., of ash constituents ; and of these sihcic 
acid in the most unequal proportion ; the ash of Nym- 
phoea alba containing less than ^ per cent, of that substance, 
while in the ash of Arundo phragmites there are above 
71 per cent. Upon the supposition just made, an equal 
amount of silicic acid is offered to the roots of both plants, 
and they both take up an equal quantity of it in proportion 
to the volume of the sap respectively. In the reed plant 
the silicic acid is incessantly withdrawn from the sap, and 
deposited in a solid state m the leaves, the margins of the 
leaves, the sheaths, &c. As the sap within contains less 
silicic acid than the solution without, fi'esh quantities of it 
are absorbed from the latter ; but not so with the Nym- 
phoea, because the sihcic acid taken up by that plant is 
not consumed in it. 

If we accept the same reasons for the passage into the 
plant of carbonic acid and phosphoric acid, then it 
can possess no actual power of selection, but the permea- 
tion of the nutritive substances will depend upon osmotic 
conditions. 

It certainly cannot be denied that the absorption of 
nutritive substances depends upon growth or increase in 
mass ; for as it is certain that a plant will not grow if no 
food is offered to it, so it is equally certain that it will 
absorb no nutriment if the external conditions are not 
favourable to growth. Yet the view given above would 
force us to conclusions which are not founded in nature ; 



60 THE PLANT. 

such as, for instance, (1) that there is actually around the 
roots a solution containing all the ash constituents of the 
plants ; and (2) that the roots of all plants have a similar 
structure, and their sap is of the same nature. 

With regard to the roots, the most common observa- 
tions appear to show that they possess the power of 
selecting the proper mineral nutriment for the plant from 
the matters presented to them. All plants do not thrive 
equally well in the same soil ; one kind succeeds best in 
soft water, another in hard water, or water abounding in 
lime ; another only on marshy ground ; many on fields 
rich in carbon and carbonic acid, such as the turf-plants ; 
others again on soil containing large quantities of alkaline 
earths. Many mosses and hchens will grow only on 
stones, the surfaces of which they sensibly change ; others, 
like Koleria, possess the faculty of extracting from sili- 
cious sandstone potash and the phosphoric acid so sparingly 
present in it. Eoots of grass attack the felspar rocks, 
accelerating their disintegration. Eapes and turnips, san- 
foin and lucerne, as also the oak and beech, receive the 
chief part of their food from the subsoil poor in humus ; 
while the cereal and tuberous plants thrive best in 
the arable surface soil, and in soil abounding in humus. 
The roots of many parasitic plants are absolutely unable 
to extract from the soil their necessary food ; but this is 
prepared for them by the roots of the plants on which 
they grow. Others again, as certain fungi, grow only on 
vegetable and animal remains, whose azotised and un- 
azotised substances they use for their own construction. 

These facts, accepted in their true significance, seem 
sufficient to remove all doubt respecting the different 
action of the roots of plants upon the soil. We know that 
common Lycopodium (club-moss) and ferns absorb alu- 
mina ; yet we also know that this substance, in the form 



ALUMINA IN PLANTS. 61 

in wliich it occurs in all fertile soils, is not soluble in pure 
water, or water containing carbonic acid ; and that it 
cannot be detected in any other plant growing on the 
same soil by the side of the club-moss. In like manner, 
Schultz-Fleeth could not discover in the water in which 
Arundo phragmites (one of the plants most abounding in 
sihcic acid) was growing, sufficient silicic acid to yield a 
ponderable amount in the composition of 1000 parts of 
the water. 



62 



CHAPTER II. 

THE SOIL. 

The soil contains tlie food of plants — Soil and subsoil ; conversion of the 
latter into the former — Power of the soil to withdraw the food of 
plants from solution in pure and in carbonic acid water ; similar action of 
charcoal ; process of surface attraction ; chemical decomposition often 
accompanies this attraction of the food of plants in the soil ; general 
resemblance of the soil in its action to animal charcoal — All arable soils 
possess the power of absorption, but in different degrees — Mode of the 
distribution of the food of plants in the soil ; chemically and physically 
fixed condition of the food — Only the physically fixed are available to 
plants, being made soluble by the roots — Power of the soil to nourish 
plants ; on what dependent — Comportment of an exhausted soU in 
fallow — Means for making the chemically fixed elements of food avail- 
able to plants — Action of air, weather, decaying organic matters and 
chemical means — Distribution of phosphoric and silicic acids ; influence 
of organic matters — Action of lime — Process of the absorption of food 
from the soil by the extremities of the roots — Mechanical preparation of 
the soil ; its influence on the growth of plants ; chemical means for pre- 
paring the soil — Rotation of crops ; its influence on the quality of the 
soil ; action of draining — Plants do not receive their food from a solu- 
tion circulating in the soil ; examination of drain ; lysemeter, spring and 
river water : bog water, food of plants contained in it ; Briickenauer 
spring water contains volatile fatty acids ; amount of food of plants in 
natural waters dependent on the nature of the soil through which they 
flow — Mud and bog earth as manure ; explanation of their action — 
Manner in which plants take up their food from the soil ; experunents on 
the growth of plants in solutions containing their food ; similar experi- 
ments with soil containing the food in a physically fixed state — Intimate 
connection of natural laws — Average crop ; necessaiy quantity of assimi- 
lable food in the soil for the production of such ; importance of the ex- 
tent of surface of the food in the soil ; the root surface — Quantity of 
food for a given surface of roots necessary for a wheat or rye crop — 
Analysis of the soil of a field — Difference between fertility and produc- 
tive power of a field — Mode of estimating relative extent of root sur- 
faces — Conversion of rye into wheat soil ; quantity of food necessary for 
the purpose ; the plan impracticable — Immobility in the soil of the food 
of plants ; experience in agriculture — Real and ideal maximum produc- 



THE SOIL CONTAINS THE FOOD OF PLANTS. 63 

tion — Conversion in practice of the chemically fixed food into an available 
form — Eifect of a manure depends upon the property of the soil — 
Improper relative proportions of the different elements of food in the 
soil : eifect of this upon the different cultivated plants : means for restor- 
ing the proper relative proportions. 

FEOM the soil plants receive the food necessary for 
their developement ; hence an acquaintance with its 
chemical and physical properties is important in helping 
us to understand the nutritive processes of plants, and the 
operations of agriculture. As a matter of course, a soil 
to be fertile for cultivated plants, must, as a primary 
condition, contain in sufficient quantity the nutritive 
substances required by those plants. But chemical 
analysis which determines this relation gives but rarely 
a correct standard by which to measure the fertility of 
different soils, because the nutritive substances therein con- 
tained, to be really available and effective, must have a 
certain form and condition, which analysis reveals but 
imperfectly. 

Eough uncultivated ground, and soil formed from the 
dust and dried mud of the highroads, are speedily 
overgrown with weeds, and though often still unfit for 
the cultivation of cereal and kitchen plants, may yet 
prove not unfruitful for other plants, requiring, like 
clover, sanfoin, and lucerne, a large amount of food, 
and which are often seen thriving luxuriantly on the 
slopes of railway embankments formed of earth that has 
never been under cultivation. A similar relation is 
shown by the subsoil of many fields. In many of them 
the earth from the deeper layers improves the surface 
soil, and increases its fertility ; in others, the subsoil mixed 
with the surface soil destroys the fertihty of the latter. 

It is a remarkable fact that rough uncultivated soil, 
unsuited for cereal and kitchen plants, may by diligent 
cultivation during several years, and by the influence 



64 THE SOIL. 

of the weather, become fertile enough to produce those 
plants which it formerly refused to bear. The dif- 
ference between fertile arable land and barren untilled 
soil is not the result of anj dissimilarity in the nutri- 
tive substances which they contain ; because in cul- 
tivation upon a large scale, to convert the untilled rough 
soil into fertile arable land, the ground, so far from being 
enriched, is rather impoverished by the cultivation of 
other plants on it. 

The difference between the subsoil and the arable sur- 
face soil, or the crude and the cultivated soil, supposing 
that both contain the same amount of nutritive substances, 
can only be founded upon this, that the cultivated ground 
contains the nutritive substances of plants, not only in a 
more uniform mixture, but also in another form. 

Now as from the influence of cultivation and weather 
above-mentioned, the rough soil acquires the power of 
furnishing the elements of food which it contains, in just 
the same quantity and in the same time as cultivated soil, 
a power which was formerly wanting in it with regard to 
certain plants, it cannot be denied that an alteration must 
have taken place in the original form and fashion of these 
elements. 

Suppose we have a soil consisting of disintegrated 
rocks : in the smallest particles of such a soil, the nutri- 
tive substances of plants, as potash for instance in a 
silicate, are retained in combination by the chemical 
attraction of silicic acid, alumina, &c. This attraction 
has to be overcome by one still more powerful, if the 
potash is to be hberated and made available for passing 
into plants. If we find that some plants are perfectly 
developed in a soil of the kind, which remains unfruitftd 
for others, we are led to assume that the former are able 
to overcome the chemical resistances opposed to their 



A SOIL WHEN SAID TO BE PEETILE. 65 

growtli, and tliat the latter are not. Further, if we find 
the same soil gradually acquiring the power of producing 
these latter plants also, we can assign no other reason 
than this, that by the combiued action of air, water, and 
carbonic acid, aided by mechanical operations, the chemi- 
cal resistances have been overcome, and the alimentary 
substances have been reduced to a form in wliich they are 
available for absorption even by plants endowed with the 
feeblest powers of vegetation. 

A soil can only then be said to be perfectly fertile for 
a given species of plant, e.g. wheat, when every part of 
its horizontal section wliich is in contact with the roots 
contains the amount of food required by the plant, in a 
form allowing the roots to absorb such food at the proper 
time, and in the proper quantity, during every stage of 
its developement. 

In a former section mention has been made of a 
property possessed by arable soil, viz. that when 
brought into contact with solutions of the articles of 
food most essential for plants in pure water or in water 
containing carbonic acid, it can withdraw these elements 
of food from such solutions. This power throws Hght 
upon the form and condition in which these materials arq 
contained or combined in the soil. 

To estimate this property correctly in its bearing upon 
the life of plants, we must call to mind a similar property 
in charcoal, which, hke arable soil, withdraws from 
many fluids colouring matters, salts and gases. 

This power in charcoal depends upon a chemical 
attraction proceeding from its surface, and the materials 
withdrawn from the fluid adhere to the charcoal in 
exactly the same way that the colouring matter adheres 
to the fibre of coloured stuffs coated over with it. 

The property of decolorising coloured fiuids, whicli 

F 



ee THE SOIL. 

animal wool and vegetable fibre share in common with 
charcoal, is perceptible in those kinds of charcoal only 
which possess a certain degree of porosity. 

Powdered pit coal, and the shining, smooth, bhstered 
charcoal from sugar or blood, have hardly any decolorising 
action ; whereas porous blood-charcoal and bone-charcoal 
with its fine pores exceed all other varieties in this 
property. 

Among the wood-charcoals, those made from poplar or 
pine, having wide pores, are inferior to the charcoal of 
the beech and box tree ; all these varieties decolorise in 
proportion to the extent of surface which attracts colour- 
ing matter. The attractive force which charcoal exercises 
upon colouring matter is about on a par with the feeble 
affinity of water for salts, which are dissolved by it, but 
without alteration of their chemical properties. When 
dissolved in water, a salt simply assumes the fluid state, 
and its particles acquire mobility ; but in all other 
respects it retains its characteristic properties, which, as 
is well known, are completely destroyed by the action of 
a stronger affinity than that of water. 

In this respect the attraction of charcoal resembles that 
of water, for both attract the dissolved matter. If the 
attraction of the charcoal is somewhat greater than that 
of the water, then the colouring matter is completely 
withdrawn from the water ; if the attraction of both is 
equal, a division takes place, and the extraction is only 
partial. 

The materials attracted by the charcoal retain all their 
chemical properties, and continue unaltered, merely losing 
their solubihty in water ; yet very slight circumstances, 
increasing in the least degree the attractive force of the 
water, are sufficient again to withdraw from the charcoal 
the materials absorbed by it, and which simply coat its 



ABSOEPTIVE POWER OF SOILS. 67 

surface. By a slight addition of alkali to tlie water the 
colouring matter may be discharged from the charcoal 
which has been used to decolorise the fluid, and by 
treatment with alcohol, the quinine or strychnine ab- 
sorbed by charcoal from a fluid may be again extracted. 

The arable soil possesses, in these respects, the same 
properties as charcoal. Diluted liquid manure, of deep 
brown colour and strong smell, filtered through arable 
soil, flows off" colourless and inodorous ; and not merely 
does it lose its smell and colour, but the ammonia, 
potash, and phosphoric acid which it holds in solution, 
are also more or less completely withdrawn from it by the 
soil, and this in a far greater degree than by charcoal. 
The rocks which by disintegration give rise to arable 
soil, if reduced to a fine powder, are just as httle pos- 
sessed of this power as pounded coal. On the contrary, 
contact with pure water or water containing carbonic acid, 
deprives many sihcates of potash, soda, and other consti- 
tuents, a clear proof that the former cannot possibly with- 
draw the latter from the water. There is no perceptible 
connection between the composition of a soil and its power 
of absorbing potash, ammonia, and phosphoric acid. A 
soil abounding in clay, with a small proportion of lime in 
it, possesses this absorptive power in the same degree as a 
lime soil with a small admixture of clay ; but the amount 
of humus substances will alter the absorptive relation. 

By a closer observation we perceive that the absorptive 
power of arable soil differs in proportion to its greater or 
less porosity ; a dense, heavy clay soil and a loose sandy 
soil possess the absorptive power in the smallest degree. 

There can be no doubt that all the component parts of 
arable soil have a share in these properties, but only when 
they possess a certain mechanical condition, like wood or 
animal charcoal ; and that this power of absorption 

F 2 



68 THE SOIL. 

depends, as in charcoal, upon a surface attraction, wliich 
is termed a physical attraction, because the attracted 
particles enter into no chemical combination, but retain 
their chemical properties.* 

The arable soil owes its formation to the disintegration 
of minerals and rocks, brought about by the action of 
mighty mechanical and chemical agencies. Though the 
comparison may not be altogether apt, the rock may be 
said to stand in about the same relation to the arable soil 
resulting from its disintegration as the wood or the vege- 
table fibre to the humus resulting from its decay. 

The same causes which in the course of a few years 
convert wood into humus act also upon rocks, with this 
difference, however, that it requires the combined action 
of water, oxygen, and carbonic acid, for probably a 
thousand years, to produce from basalt, trachyte, felspar, 
or porphyry, the thinnest layer of arable soil (such as is 
found in the plains of river valleys and low lands) with 
all the chemical and physical properties suited for the 
nutrition of plants. Sawdust possesses the properties of 
humus no more than powdered rocks have the properties 
of arable soil. No doubt sawdust may pass mto humus 
and powdered stones into arable soil, but the two states 
are .essentially distinct ; and no human art can imitate the 
operations which were necessary, during immense ages, 
to convert the divers kinds of rocks into arable soil. 

Arable soil, resulting from the disintegration of various 
kinds of rocks, bears the same relation, in respect of 
absorptive power for inorganic substances in solution, as 
the woody fibre altered by the action of heat bears to 
organic substances in solution. 

* The term, ' physical attraction,' as used here, does not signify a 
pectUiar attractive force, but merely designates the ordinary chemical 
affinity, which shows differences of degree in its manifestation. 



AEABLE SOIL COMPAEED TO ANIMAL CHAECOAL. 69 

It has been stated, that from a sohition of carbonate of 
potash or ammonia, or from a sohition of phosphate of 
hme in carbonic acid water, the arable soil will withdraw 
the potash, ammonia, and phosphoric acid, without any 
chemical interchange with the constituents of the earth 
taking place. In this respect the action of arable soil is 
absolutely hke that of charcoal. But it goes farther, for it 
is sufficiently powerful to sever the connection between 
the potash or ammonia and the mineral acid, for which 
they have the greatest affinity, the potash being absorbed 
by the soil just as though it were not combined with 
an acid. 

In this property arable soil is like animal charcoal, 
which, by means of the phosphates of the alkahne earths 
contained in it, decomposes many salts that are not 
affiscted by charcoals free from such phosphates ; and, 
without doubt, the lime and magnesia compounds in- 
variably present in arable soil have a share in this 
decomposing power which it possesses. 

We must suppose that the attractive force of the earthy 
particles would not in itself be strong enough to separate, 
for instance, potash from nitric acid, and that it requires 
the additional attraction of the lime or magnesia to de- 
compose the nitrate of potash. On the one side the soil 
attracts the potash, on the other the hme or magnesia in 
the earth attracts the nitric acid, and thus the combined 
attraction effi3cts, as in innumerable instances in chemistry, 
a separation which could not have been brought about by 
a simple one. 

The process of decomposition effected by arable soil 
differs only in one respect from the ordinary chemical 
processes, namely, that in the latter, as a general rule, no 
soluble potash salt is decomposed by an msoluble hme 
salt, in such a manner that the potash is thereby made 



70 THE SOIL. 

insoluble and the lime soluble. There is evidently here 
some other attractive force at work, which alters the 
effect of chemical affinity. If a solution of phosphate of 
lime in water containing carbonic acid is filtered through 
a funnel filled with earth, the uppermost layer of the 
earth first takes up the phosphoric acid or the phosphate 
of hme from the fluid. Once saturated therewith it no 
longer stops the free passage of the dissolved phosphate 
of hme which now reaches the layer beneath ; the latter 
then again becomes saturated in the same way, and thus 
by degrees the phosphate of hme is completely diffused 
throughout the earth in the funnel, so that every particle 
retains on its surface an equal proportion of this substance. 
If the phosphate of lime were of the colour of madder and 
the soil colourless, the latter would now actually present 
the appearance of a madder lake. Just in the same way 
potash is diffused through the soil when a solution of 
carbonate of potash is filtered through it ; the lower 
layers receive what the upper do not retain. 

There is no need of any special disquisition to show 
that the phosphate of lime contained in a particle of bone- 
earth is diffused in exactly the same way through arable 
soil, with this difference, that the solution of phosphate of 
lime in rain-water containing carbonic acid is effected at 
the very spot where the particle hes, and spreads thence 
downward and in ah directions. 

The potash and the silicic acid rendered soluble by 
disintegration, or by the action of water and carbonic acid 
upon sihcates, are diffused through the soil in the same 
way, so is ammonia also, which is conveyed m ram- water, 
or is generated by the putrefaction of the azotised consti- 
tuents in the decayed roots from the successive generation 
of plants grown on a field. 

Every soil must therefore contain potash, silicic acid 



FOOD PHYSICALLY AJ^B CHEMICALLY COMBINED. 71 

and phosphoric acid in two different forms, namely, in 
chemical and in physical combination : in the one form, 
infinitely diftiised over all the surface of the porous par- 
ticles of the soil ; in the other, in the shape of granules 
of phosphorite, or apatite and felspar, very unequally 
distributed. 

In a soil abounding in silicate and in phosphate of lime, 
v^hich has for thousands of years been exposed to the dis- 
solving action of water and carbonic acid, the component 
particles will be found everywhere physically saturated 
with potash, ammonia, sihcic acid, and phosphoric acid ; 
and it may occur, as in the case of the so-called Eussian 
black-earth, that the phosphate of lime dissolved but not 
absorbed is deposited again in concretions, or in a crystal- 
hne form in the subsoil. 

In this state of physical combination the alimentary 
substances are manifestly in the most favourable condition 
to serve as food for plants ; for it is clear that the roots, 
in all places where they are in contact with the soil, will 
find the necessary nutritive substances in the same state 
of diffusion and readiness as if these substances were in 
solution m water, but at the same time not movable of 
themselves, and retained in the soil by so shght a force 
that the most trifling dissolvent cause brought to bear 
upon them suffices to effect their solution and transition 
into the plant. 

If it is true that the roots of cultivated plants have no 
inherent power to overcome the force which retains 
together potash and sihcic acid in the sihcates, but that 
those elements of food only which are in physical com- 
bination with the soil can be taken up and made avail- 
able for nutriment, this explains the difference between 
cultivated and uncultivated ground, or barren subsoil. 

Nothing can be more certain than that the mechanical 



72 THE SOIL. 

treatment of the soil and the influence of the weather 
serve to strengthen the causes which bring about the 
disintegration and decomposition of the minerals, and the 
uniform distribution of the elements of food contained 
in them and rendered soluble. The elements chemically 
combined in the minerals are released from that com- 
bination, and in the arable soil gradually resulting from 
this decomposition acquire the form in which they are 
available as food for plants. It is evident that only by 
degrees the rough ground can attain the properties of arable 
soil, and that the time required for this change depends 
upon the quantity of nutritive substances present, and 
upon the obstacles which oppose their distribution, or 
their disintegration and decomposition. The perennial 
plants, and particularly the so-caUed weeds, consuming in 
proportion to the time less food, and absorbing longer, 
will always thrive on a soil of this description long before 
annual or summer plants, which in their shorter period 
of vegetation require a far larger amount of nutritive 
substances for their full developement. 

The longer a soil is under cultivation, the more it 
becomes suited for the growth of summer plants, from 
the recurrence and operation of the causes by which the 
nutritive substances are converted from a state of chemical 
into one of physical combination. To be productive, in 
the fullest sense of the term, a soil must be able to afford 
food at all points in contact with the roots of the plants ; 
and, however small the quantity of this food may be, it 
must necessarily be distributed through every part of the 
soil. 

Tlie power of the soil to nourish cultivated plants is 
therefore in exact proportion! to the quantity of nutritive 
substances ivhich it co7itains in a state of physical satura- 
tion. The quantity of the other elements in a state of 



FOOD PHYSICALLY COMBINED. 73 

chemical combination distributed through the ground, is 
also highly important, as serving to restore the state of 
saturation, when the nutritive substances in physical com- 
bination have been withdrawn from the soil by a series of 
crops reaped from it. 

Experience proves that the cultivation of deep-rooting 
plants, which draw their food principally from the subsoil, 
does not materially impair the fertihty of the surface soil 
for a succeeding crop of cereal plants ; but the suc- 
cessive cultivation of the latter will, in a comparatively 
small number of years, render the soil incapable of 
yielding a remunerative crop. 

With most of our cultivated fields this state of exhaus- 
tion is not permanent. If the ground is left fallow for 
one or more years, especially if it is well ploughed and 
harrowed during the time, it recovers the power of 
yielding a remunerative crop of cereal plants. 

Chemical analysis leaves altogether unexplained the 
causes of this fact, so highly important to agriculture, and 
which has been fully estabhshed by the experience of 
several thousand years. If the reason be that cereal 
plants feed on those substances only which are in physical 
combination in the surface soil, then we can easily under- 
stand the remarkable fact of a field recovering its power 
of production without any supply of manure ; for though 
the nutriment in this form constitutes but a small portion 
of the soil by weight, yet it imparts nutritive qualities to a 
large volume of it ; and it is quite intelligible that a soil 
not originally rich in nutritive substances physically com- 
bined, when drained of them by the innumerable under- 
ground absorptive organs of a plant, must very speedily 
become unsuited for the cultivation of that plant. 

Now as the cultivated soil is composed in the main of 
ingredients which are identical with the constituents of 



74 THE SOIL. 

uncultivated ground, and as tlie agencies effecting the 
decomposition of these ingredients and the transposition 
of their constituents affording food to plants are in 
constant operation, it is easy to conceive how, by the 
influence of such causes, an exhausted soil, which is in 
fact nothino; else than a soil reduced to its crude state 
previous to cultivation, must regain the properties wliich 
it had lost. With the conversion of a fresh portion of the 
food elements from a state of chemical to one of physical 
combination, the field recovers the power of affording 
food to a fresh vegetation in such quantity that the crops 
are again remunerative to the agriculturist. 

An exhausted field which is again rendered productive 
by fallowing, may accordingly be defined as land deficient 
in physically combined nutritive substances necessary for 
a full crop, while containing an excess of such substances 
in a chemically combined state. The falloiving season, 
therefore, means the time in which the nutritive sub- 
stances pass over from the one state to the other. It is 
not the amount of nutritive substances that is increased 
in fallowing, but the number of particles of their con- 
stituents capable of affording nutrition. 

What is here asserted of all the mineral nutritive sub- 
stances without distinction appHes equally to every soil 
constituent required by the plant. The exhaustion of a 
field may often simply depend upon a deficiency of 
available silicic acid for the coming crop of cereal 
plants, while the other food elements may be super- 
abundant. 

It is evident from the nature of the process, that if 
the soil is altogether deficient in disintegrable silicates or 
soluble earthy phosphates, the action of time, the plough, 
and the weather in fallow will not restore fertility to a 
field, and that the effect of disintegrating causes will vary 



CONDITIONS FOE EENDEEING FOOD AVAILABLE. 75 

mtli tlie time tliey are in operation, and with the com- 
position of the different soils. 

It clearly results from the foregoing observations, that 
one of the principal requirements of the practical farmer 
is to know the causes as well as the means whereby the 
useful nutritive substances present in his field, but not in 
a form available for nutrition, may be rendered diffusible 
and capable of doing their work. 

The presence of moistm^e, a certain degree of heat, and 
free access of air, are the proximate conditions of those 
changes by which the nutritive substances in chemical 
combmation are made available for the roots. A certain 
quantity of water is indispensable to transpose the sod- 
constituents when rendered soluble ; water, with the co- 
operation of carbonic acid, decomposes the sihcates, and 
makes the undissolved phosphates soluble and diffusible 
through the soil. 

The organic remains decaying in the ground afford 
feeble but long-continued sources of carbonic acid ; but 
without moisture no process of decay can take place. 
Stagnant water, again, which excludes the access of au% 
prevents the 'generation of carbonic acid ; and the pro- 
cess of putrefaction is attended with the generation of 
heat, whereby the temperatm-e of the soil is perceptibly 
increased. 

By the aid of putrescent vegetable and animal remains, 
a field exhausted by cultm^e will regain its fertility in 
a shorter time, and the use of farm-yard manm-e in 
time of fallow will promote the process. The dense 
shadow cast by a leafy plant tends to retain moisture 
longer in the ground, and thus increases the action of 
the disintegratuig agencies during the faUow season. 

In a porous soil aboundmg in hme the putrefactive 
process of organic matter proceeds much more quickly 



76 THE SOIL. 

than in a clay soil ; the presence of the alkahne earth, 
under these circumstances, serving to oxidise the car- 
bonaceous matter, and to convert the ammonia present in 
the soil into nitric acid. 

All kinds of lime, when hxiviated, give up nitrates to the 
water. Nitric acid is not retained by the porous earth, 
as is ammonia ; but it is carried down combined with 
lime or magnesia by the rain-water into the deeper layers 
of the soil. While the formation of nitric acid taking 
place in the ground is useful for plants which, like clover 
and peas, draw their food (here including nitrogen) from 
a greater depth, yet for this very reason fallowing has a 
less beneficial effect, with a view to the culture of 
cereal plants, upon a lime soil rich in animal remains ; 
for by the conversion of ammonia into nitric acid, and its 
removal, the ground becomes poorer in one of the most 
important elements of the food of plants. The case is 
conceivable that a field of the kind, if not cultivated for 
a number of years, may ultimately have its productive 
powers impaired by a deficiency of nitrogenous food in 
the soil. 

The cause of the exhaustion of a field by the culture 
of any plant is always, and under all circumstances, 
dependent upon a deficiency of one or more nutritive 
substances in those portions of the soil which are in con- 
tact with the roots. A field in which these portions are 
deficient in phosphoric acid in the state of physical com- 
bination, will be found unsidted for the production of a 
proper crop, though it should contain abundance of avail- 
able potash and sihcic acid. The same results will follow 
from a want of potash, even though phosphoric and silicic 
acids be plentiful ; and equally so from a want of silicic 
acid, hme, magnesia, or iron, even where potash and 
phosphoric acid are in abundance. 



MEANS FOR CAUSING THE DIFFUSION OF FOOD. 77 

When the exhaustion of a field is not caused by the 
absolute deficiency of food elements, when even a more 
than adequate supply of all the needful nutriment is there, 
but not in the proper form, and where consequently fal- 
lowing will again render the crop remunerative, the farmer 
has means at his disposal to assist the action of the natural 
agencies, whereby the conversion of the food elements 
into the state of physical combination is efiected, and 
thus to shorten the fallowing season, or even in many 
instances to make it altogether superfluous. 

We have seen that the diffusion of earthy phosphates 
through the soil is effected exclusively by water, which, 
if containing a certain amount of carbonic acid, dissolves 
these earthy salts. 

Now, there are certain salts, such as chloride of sodium, 
nitrate of soda, and salts of ammonia, which experience 
has proved to exercise, under certain conditions, a favour- 
able action upon the productiveness of a field. 

These salts, even in their most dilute solutions, possess, 
hke carbonic acid, the remarkable power of dissolving 
phosphate of hme and phosphate of magnesia ; and when 
such solutions are filtered through arable soil, they behave 
just like the solution of these phosphates in carbonic acid 
water. The earth extracts from these salt solutions the dis- 
solved earthy phosphates, and combines with the latter. 

Upon arable soil mixed with earthy phosphates in 
excess, these salt solutions act in the same way as upon 
earthy phosphates in the unmixed state, that is, they dis- 
solve a certain proportion of the phosphates. 

Nitrate of soda and chloride of sodium suffer, by the 
action of arable soil, a similar decomposition to that of 
the salts of potash. Soda is absorbed by the soil, and 
in its stead Hme or magnesia enters into solution in 
combination with the acid. 



78 THE SOIL. 

If "we compare the action of arable soil upon salts of 
potash and salts of soda, we find that the soil has far less 
attraction for soda than for potash ; so that the same 
volume of earth which will suffice to remove all the pot- 
ash from a solution wiU, in a solution of chloride of 
sodium or nitrate of soda of the same alkaline strength, 
leave undecomposed three-fourths of the dissolved chlo- 
ride of sodium and half of the nitrate of soda. 

If, therefore, a field exhausted by culture, which con- 
tains earthy phosphate scattered here and there, is 
manured with nitrate of soda or chloride of sodium, and 
by the action of rain a dilute solution of these salts is 
formed, a portion of them will remain imdecomposed in 
the ground, and must in the moist soil exert an influence, 
weak in itself, but sure to tell in the long run. 

Like carbonic acid generated by the putrefaction of 
vegetable and animal substances, and dissolving in water, 
these salt solutions become charged with earthy phos- 
phates in all places where these occur. Now when these 
phosphates diffused through the fluid come into contact 
with particles of the arable soil not already saturated with 
them, they are thereby withdrawn from the solution, and 
the nitrate of soda or chloride of sodium remaining in 
solution again acquires the power of repeatedly exerting 
the same dissolving and diffusing action upoii phosphates 
which are not already fixed in the soil by physical attrac- 
tion, untfl. these salts are finally carried down by rain- 
water to the deeper layers of the soil, or are totally 
decomposed. 

It is well-known that chloride of sodium is present in 
the blood of all animals, and that it plays a part in the 
processes of absorption and secretion ; hence it may be 
regarded as indispensable for these functions. We find 
also that nature has endowed fodder-plants, tuberous and 



ACTION OF SALTS OF AMMONIA ON PHOSPHATES. 79 

root-plants, whicli serve more particularly as food for 
cattle, with a greater power of taking up cliloride of 
sodium from the soil than is possessed by other plants ; 
and agricultural experience shows that the presence 
of a small amount of common salt is favourable to the 
luxuriant growth of these plants. 

Of nitric acid, it is generally assumed that it may, hke 
ammonia, serve to sustain the body of the plant. Thus, 
chloride of sodium and the nitrates act in two distinct 
ways : one direct, by serving as food for the plant ; one 
indu^ect, by rendering the phosphates available for the 
purposes of nutrition. 

The salts of ammonia act upon earthy phosphates in 
the same way as the salts just mentioned, but with this 
distinction, that their power of dissolving phosphates 
is far greater ; a solution of sulphate of ammonia will 
dissolve twice as much bone-earth as a solution of an 
equal quantity of chloride of sodium. 

However, as regards the phosphates in the soil, the 
action of the salts of ammonia can hardly be more 
powerful than that of chloride of sodium or nitrate of 
soda, since the salts of ammonia are decomposed by the 
soil much more speedily, and often even immediately ; so 
that, as a general rule, no solution of such a salt can be 
said to be actually moving about in the soil. But as a 
certain volume of earth, however small, is requu-ed to 
decompose a given quantity of salts of ammonia, the 
action of those salts upon this small volume of earth 
must be all the more powerful. While, then, the action 
of salts of ammonia is barely perceptible in the somewhat 
deeper layers of the arable surface soil, that which they 
exercise on the uppermost layers is so much the stronger. 
Feichtinger observed that solutions of salts of ammonia 
decompose many silicates, even felspar, and take up 



80 THE SOIL. 

potash from the latter. Thus, by their contact with the 
arable soil, they not only enrich it with ammonia, but 
they effect, even in its minutest particles, a thorough 
transposition of the nutritive substances required by 
plants. 

The vegetable and animal remains in a soil seem to 
exercise a remarkable influence upon the diffusion of 
sihcates. The experiments made on this point show 
that the absorptive power of an arable soil for sihcic 
acid is in an inverse ratio to the amount of organic 
remains in it ; so that a soil rich in such remains will, 
when bi'ought into contact with a solution of silicate of 
potash, leave a certain amount of sihcic acid unabsorbed, 
whereas an equal bulk of soil poor in organic remains 
will take up the whole of the silicic acid in the solution. 
The incorporation of decaying vegetable and animal 
matter wiU, therefore, in a soil containing disintegrable 
sihcates, first of aU accelerate the decomposition of the 
sihcates, by the action of the carbonic acid generated in 
the process of decay, and then, as these substances 
diminish the absorptive power of the soil for silicic 
acid, as soon as this acid has passed into solution, 
it is distributed through the soil more widely than 
would have been the case had these substances not been 
present. 

On many fields poor in clay, the growth of grass for 
several years will, in consequence of the organic matters 
coUecting in the soil, which serve to promote the distri- 
bution of the silicic acid, act more favourably on a suc- 
ceeding crop of a cereal plant than a plentiful apphcation of 
farm-yard manure, whose organic constituents, quite irre- 
spective of the silicate of potash in the straw, are always 
in operation to effect the same object. On many other 
fields, especially on those abounding in lime, where there 



DEFICIENCY OR EXCESS OF SOLUBLE SILICIC ACID. 81 

is no actual deficiency of silicic acid, but the quantity 
present is not properly distributed through the soil, a 
dressing of pulverised turf-waste often produces an 
equally favourable effect on a succeeding cereal crop as 
a plentiful application of farm-yard manure. 

Deficiency or excess of soluble silicic acid in the 
ground is equally injurious to the growth of cereal 
plants. A soil which would answer very well for horse- 
tail or common reed [Arundo phragmites, plants abound- 
ing in sihca) is not on that account equally well suited 
for the superior kinds of meadow grass, or for cereals, 
although these demand a rich supply of silicic acid. 
Such a soil may be improved by drainage, which, by 
giving free access to air, decomposes and destroys the 
organic substances present in excessive quantity ; or it 
may derive benefit from a dressing of marl, or of burnt 
hme, slaked, or fallen to powder by moist air. 

Hydrated silicic acid loses its solubility in water by 
simple drying, and it frequently happens that the drainage 
of a marshy field will cause the siliceous plants (reeds and 
horsetail) to disappear. The action exerted upon the 
soil by hydrate of lime, or by hme slaked or fallen to 
powder in the air, is twofold. On a soil rich in humus 
constituents the hme combines, in the first place, with 
the organic compounds present, which have an acid 
reaction ; it neutralises the acid of the soil, thereby 
causing the speedy disappearance of many weeds, such as 
bog-moss [Sphagnum) and reed-grasses, which flourish 
in a sour soil of this kind. Simple contact with acids 
powerfully promotes the oxidation of metals (copper, 
lead, iron), while contact with an alkali prevents it 
(iron coated with a dilute solution of carbonate of soda 
will not rust). Upon organic substances, the action is 
the very reverse : acids prevent, and alkahs promote, 

G 



82 THE SOIL. 

oxidation or decay. Excess of lime causes the aforesaid 
destruction of the humose constituents. 

In the same degree as the acid humus, by the action 
of Hme, disappears from the ground, the absorptive 
power of the latter for hydrated silicic acid is increased ; 
and the excess of this acid present loses its mobility in 
the soil.* 

The action of lime, as we see, is so complex, that from 
its favourable influence upon one field, it is scarcely ever 
possible to form an opinion of its probable action upon 
another field, the condition of which is unknown. This 
is possible only when the causes of its favourable action 
in the first case are clearly understood. 

When lime has improved the condition of a field, simply 
by neutrahsing the acid state of the soil, and destroying 
the injurious excess of vegetable remains, the farmer will 
in vain expect a favourable result from the apphcation of 
lime in the following years, unless the same causes should 
recur which had originally impaired the fertility of the 
field. 

In a soil wherein there are putrescent and decaying 
substances not a single plant will thrive, except mush- 
rooms ; and it seems that every chemical process going on 
in the neighbourhood of roots disturbs that of their own. 
Decaying substances in excess, by generating too much 
carbonic acid, injure even those plants which thrive par- 

* In an experiment made specially for the purpose, it Avas 
found that a litre (about a quart) of forest soil, containing 30- per 
cent, of humose constituents, absorbed from a solution of silicate 
of potash only 15 milligrammes of silicic acid. But the same soil 
mixed with 10 per cent, of washed chalk (carbonate of lime) ab- 
sorbed 1140 milligrammes; and when mixed with 10 per cent, 
of slaked lime instead of chalk, the absorptive power Avas increased 
to such a degree, that a litre absorbed 31(39 milligrammes of silicic 
acid. 



BENEFICIAL ACTION OP LIME. 83 

ticularly well in a liumose soil containing a moderate 
quantity of humus.* 

Upon deep-rooting plants, such as turnips, clover, san- 
foin, peas and beans, organic matters accumulating largely 
in the subsoil act very injuriously, especially in clay, 
where they decay much more slowly than in a lime soil. 
The process of decay is communicated to the sickening 
roots, in which spores of fungi find a suitable soil for their 
developement. When turnips are thus affected, they be- 
come the prey of certain insects, which deposit their eggs 
in the roots, causing m their developement a strange 
alteration and disturbance of the vegetative process ; for 
in the diseased parts spongy tumours arise, the inner sub- 
stance of which becomes soft and emits a bad smell, and 
in this state serves to nourish the larva of the small fiy. 

All these processes, however obscure in themselves, are 
put an end to by applying lime to such a field ; a proper 
hme dressing will always attain this object. Fields that 
are particularly rich in organic remains require a much 
larger supply of lime than others, to effect their restora- 
tion to a healthy state. 

It is certain, that in all such cases, the beneficial action 
of the lime is not attributable to an original deficiency of 
that body in the soil for plants growing on it ; for in that 
case, considering the rapidity with which it is diffused 

* Grasparini sowed a few grains of spelt in a pot with washed earth 
from Vesuvius ; these produced plants which continued to grow in a 
healthy state. In another pot, filled with the same earth, he introduced 
a piece of bread; in this, all the roots in the immediate vicinity of 
the mouldering bread died away, and the other roots seemed to 
have turned off towards the sides of the pot. It is clear that spelt 
would not grow in a soil copioiisly mixed with bread ; and if the 
decaying roots left by a spelt crop have the same effect, it is not 
difficult to conceive how the decaying remains which a plant leaves in 
the ground, may injuriously affect its own growth, or that of other 
plants. (Russell.) 

G 2 



84 THE SOIL, 

through the soil, the effect would manifest itself very soon, 
and even in the course of the first year. But it takes 
several years before the favourable change in the condition 
of the soil is effected ; proving that the lime operates, not 
simply as food, but by producing an alteration in the soil, 
which requires time, that is, a succession of operations. 

On a drained marshy soil, in which hme has diminished 
the excess of hydrated sihcic acid, a second apphcation 
will not produce the same result, because the offensive 
substances, once removed, will not return ; while on a 
heavy, stiff clay or loam, the apphcation may be repeatedly 
successful. These kinds of soil are thereby made more 
friable and richer in available potash. The nature of the 
change produced is most clearly shown in the hydrauhc 
lime obtained by calcining native Gement-stones (a hard 
marl). These cement-stones consist of a mixture of hme 
and clay, the former being in larger proportion than in 
calcareous clay soil. After burning, if it is stirred up 
with a large quantity of water, the separated potash im- 
parts to the fluid all the properties of a weak lye. Clay 
which before calcination with lime refused to dissolve in 
acids, is, after calcination, soluble in acids to the whole 
extent of the sihcic acid present. 

A calcareous clay soil withdraws from a solution of 
silicate of potash much less potash after calcination than 
before, but a much larger quantity of silicic acid.* 

Besides the chemical agents mentioned here, which the 
farmer may employ to effect the proper distribution of the 
nutritive substances stored up in his field, and to make 

* At Bogenhausen, near Munich, loam was calcined in the air, and 
brought into contact with a solution of silicate of potash : before 
calcination, a litre of this earth took up 1148 milligrammes of potash, 
and 2007 milligrammes of silicic acid ; after calcination, no potash, 
and 3230 milligrammes of silicic acid. 



THE ROOT GOES IN SEARCH OF FOOD. 85 

the earthy phosphates, the potash, and the silicic acid 
available to the roots of the plants, he further improves 
his land by the mechanical operations of agriculture, and 
by removing from the soil all obstacles that hinder the 
spreading of the roots, as well as those injurious agencies 
which interfere mth their normal activity, or endanger 
their healthy condition. 

The effect produced by breaking up the ground by 
plough, spade, hoe, harrow, and roller, depends upon the 
fact, that the roots of plants go in search of their food ; 
that the nutritive substances have no locomotion of their 
own, and caimot of themselves leave the place in which 
they are. The root, as if it had eyes to see, bends and 
stretches in the direction of the nutriment ; so that the 
number, thickness, and direction of its filaments indicate 
the precise spots where they have obtained food.* 

The young root forces its way, not like a nail driven 
with a certaia force into a plank, but by the addition of 
successive layers, which increase its mass from within 
outwards. 

The new substance, which lengthens the extremity of 
the root, is in contact with the soil. The newer the cells 
forming at the extremities, the thinner are their walls ; 
as they grow older, the cell- walls thicken, and their outer 
surface, becoming more woody, is coated in many cases 

* Pieces of bone are often found completely enclosed by a network 
of turnip-roots. It is difHcult to understand bow tbis could bave been 
accomplisbed otherwise tban by an attraction between tbe spongioles and 
the substance of tbe bone. Tbe cells, or tbeir contents, are incessantly 
attracted by tbe fresb surface of a substance, for wbicli tbe contents 
bave a chemical attraction. 

It is owing to this attraction that the roots wind round tbe piece of 
bone ; they form a root-ball rolled, not from without, but from within, 
by tbe new cells constantly formed upon contact with a substance foy 
which they possess a chemical attraction. (Eussell.) 



86 THE SOIL. 

with a layer of corky substance, wliich, being impene- 
trable by water, affords, to the soluble matter deposited 
within, some protection against osmotic influences. 

Absorption of nutriment from the soil is effected by 
the extremities of the roots, whose fluid contents are 
separated from the earthy particles around them by an 
exceedingly thin membrane alone ; and the contact of 
the two is the more intimate, as the root-fibre during its 
formation exerts upon the earthy particles a pressure suf- 
ficiently powerful, under certain cu-cumstances, to push 
them aside. The evaporation of water from the leaves 
produces a vacuum within the plant, whereby a draught 
is created, which powerfully assists the contact of the 
moist earthy particles with the cell-waU. The cell and 
the earth are pressed against each other. Between the 
fiuid contents of the cells and the nutritive substances 
physicaUy combined in the earthy particles, there mani- 
festly exists a strong chemical attraction, which, with the 
cooperation of carbonic acid and water, causes the trans- 
ference of the incombustible matters into the system of 
the plant. 

By the powerful chemical attraction of any body, we 
understand its entering into a chemical combination, in 
which it loses its original properties and acqukes new 
ones. In the case of potash, hme, and phosphoric acid, 
such a combination must take place immediately upon 
their passage into the cell ; for, as already stated, the sap 
of the roots is always slightly acid. In the sap of the 
root-shoots of the vine, we can always detect bitartrate of 
potash ; in that of others, oxalate or citrate of potash, or 
tartrate of lime ; but we never find these bases combined 
in such saps with carbonic acid, nor can phosphate of 
lime or magnesia be detected. If tlie fresh sap of the 
potato-tuber is mixed with ammonia, no precipitate of 



DISTRIBUTION RENDERS FOOD EFFECTIVE. 87 

phospliate of magnesia and ammonia is produced ; but 
this precipitate makes its appearance as soon as the 
fermentation of the sap has destroyed the (azotised) 
substance with which the phosphate of magnesia is com- 
bined. 

Careful mixture and distribution of the nutritive sub- 
stances present in the soil, are the most important means 
of rendering them effective. 

A piece of bone, weighing half an ounce, placed in a 
cubic foot of earth, has no perceptible influence upon its 
fertihty ; but when uniformly distributed and physically 
combined with the minutest particles of the same earth, 
it attains a maximum of efficacy. The influence of the 
mechanical operations of agriculture upon the fertility of 
a soil, however imperfectly the earthy particles may be 
mixed by the process, is remarkable and often borders 
upon the marvellous. The spade, which breaks, turns, 
and mixes the soil, makes a field much more fruitful than 
the plough, which breaks, turns, and displaces the earth, 
without mixing it. The effect of both is increased by the 
harrow and the roller, so that, in the very same places 
where a crop has grown during the preceding year, a 
fresh crop will find nutriment ; in other words, the earth 
is not yet exhausted. 

The action of chemical agents in distributing the food- 
elements of plants is still more powerful than that of the 
mechanical. By applying, in proper quantities, nitrate of 
soda, salts of ammonia, and chloride of sodium, the 
farmer not only enriches his field with materials capable 
of taking part in the nutrition of plants, but he also 
effects a distribution of the ammonia and potash, thereby 
replacing or aiding the mechanical work of the plough, 
and the influence of the weather in the time of fallow. 

We are in the habit of calhng ' mamures ' all those 



88 THE SOIL. 

materials which, when apphecl to our fields, increase the 
crops ; but the same effect is produced by the plough. 
It is evident that the mere fact of a favourable influence 
exerted by chloride of sodium, nitrate of soda, salts of 
ammonia, lime, and organic matter, affords no conclusive 
proof that these have acted as nutritive substances. The 
work performed by the plough may be compared to the 
mastication of food by those special organs with which 
nature has endowed animals ; and nothing can be more 
certain' than that the mechanical operations of agriculture 
do not add to the store of nutritive substances in a field, 
but that they act beneficially by preparing the existing 
nutriment for the support of a future crop. With equal 
certainty we know that chloride of sodium, nitrate of 
soda, salts of ammonia, humus, and lime, beside the 
action pecuhar to their elements, perform also a kind of 
digestive function comparable to that of the stomach in 
animals, and in which they may partly replace each 
other. These substances, therefore, act beneficially upon 
those kinds of soil only in which there is a defect, not in 
the quantity, but in the form and condition of the nutri- 
tive elements ; and they may accordingly in their perma- 
nent action be replaced by a mechanical comminution, or 
exceedingly fine pulverisation of the soil. 

The true art of the practical farmer consists in rightly 
discriminating the means which must be applied to make 
the nutritive elements in his field effective, and in dis- 
tinguishing these means from others which serve to keep 
up the durable fertihty of the land. He must take the 
greatest care that the physical condition of his ground be 
such as to permit the smallest roots to reach those places 
where nutriment is found. The ground must not be so 
cohesive as to prevent the spreading of the roots. 

Jn a stiff, heavy soil, plants with fine, slender roots will 



EFFECT OF ORGANIC REMAINS IN THE SOIL. 89 

never thrive well, even thoiigh the supply of nutritive 
substances be ample ; and in these circumstances, the 
beneficial influence of green manure and fresh stable 
dung is unmistakeable. The mechanical condition of the 
soil is, in fact, altered in a remarkable way by the 
ploughing in of plants and their remains. A stiff soil 
loses thereby its cohesion, becoming more friable and 
crumbling, than it would be by the most diligent plough- 
ing. In a sandy soil, on the other hand, a certain cohesion 
is hereby produced. Every stem and leaf of the green- 
manure plants ploughed in, opens up, by its decay, a 
road by which the delicate roots of the cereals may 
ramify in all directions to seek their food. Here, too, 
we must always remember, that the effect calculated to 
be produced is a question of degree. In many fields, the 
roots left in the soil of a fine crop of green forage plants 
will suffice to improve a succeeding cereal crop ; and a 
field from which a crop of lupines has been taken, may 
possibly give as fine a succeeding cereal crop as a 
field of equal extent in which the lupines have been 
ploughed in. 

All these observations tend to show the great import- 
ance of the mechanical conditions which impart fertihty 
to a soil not originally deficient in the means of nourish 
ing plants ; and that a comparatively poorer but well- 
tilled soil, if its physical condition is more favourable for 
the activity and developement of the roots, may yield a 
better harvest than richer land. Li like manner, it often 
happens that the cultivation of a bulbous plant renders 
the ground better suited for a following cereal, and that 
a winter crop succeeding a green forage plant, turns out 
all the better, the richer the previous green forage crop 
has been, or rather the roots left by it. 

Clover and turnips act favourably upon a succeeding 



90 THE SOIL. 

winter crop, as their long liardy roots move the subsoil, 
which is inaccessible to the plough, and open it for the 
roots of wheat. Here the favourable influence upon the 
physical condition of the soil far outweighs, for the wheat- 
plant, the injurious effect of the decrease in the quantity 
of the chemical conditions resulting from the previous 
turnip and clover crops. Eacts of this nature have but 
too often misled practical agriculturists to surmise that the 
physical condition is everything, and that a thorough 
working and pulverisation of the soil will suffice to 
command a good crop. These views, however, have 
always been refuted by time ; and all we can consider 
established is this, that for a series of years the restoration 
of a proper physical condition in the soil is as important 
for the productiveness of many fields as manuring, and 
often more so. 

The influence of a proper physical condition of the soil 
upon the produce can hardly be more convincingly proved 
than by the facts which agriculture has derived from the 
drainage of land, under which we comprise the removal 
of the subsoil water to a greater depth, and the quicker 
withdrawal from the arable soil of the portion circulating 
in it. A great many fields unsuited, by their constant 
humidity, for the cultivation of cereal plants and the 
superior kinds of forage grasses, have been reclaimed by 
drainage, and made fit to produce food for man and beast. 
When the farmer, by means of drainage, keeps within 
bounds the amount of water in his fields, he controls its 
injurious influence at all seasons ; and by the speedier 
removal of the water, which soaks the earth and destroys 
its porosity, a path is opened for the ak to reach the 
deeper layers of the ground, and to exercise upon these 
the same beneficial influence as upon the surface soil. 

In winter, the earth at a depth of 3 or 4 feet is warmer 



ANALYSIS OF DEAINAGE WATERS. 91 

than the external atmosphere ; hence the air coming up 
from the drain-pipes may contribute to keep the tempera- 
ture of the arable surface higher than it would be without 
this current of air. The air in the drains is generally 
richer in carbonic acid than is the case with atmospheric 
air. 

The effect which drainage produces upon the fertihty 
of land may in itself be deemed a proof that plants 
cannot derive their food from the water moving about in 
the soil. This view is strongly supported by the analysis 
of well, drain, and spring water. (See Appendix D.) 

The drainage-waters contain all the substances which 
the rain-water, percolating the surface soil, is capable of 
dissolving : they contain various salts in trifling propor- 
tions, and among these mere traces of potash ; ammonia 
and phosphoric acid are generally absent. In analyses 
specially made for this purpose, Thomas Way found that 
in four (drainage) waters no appreciable quantity of potash 
could be detected in 10 pounds of water; three other 
waters were found to contam from 2 to 5 pounds of 
potash in 7,000,000 pounds of water. In three waters 
no appreciable quantities of phosphoric acid could be 
discovered : four other waters were found to contain 6 to 
12 pounds of phosphoric acid, and 0'6 to 1*8 pounds of am- 
monia in 7,000,000 pounds of water. In a similar series 
of analyses, Krocker found that m six drainage-waters 
no appreciable traces of phosphoric acid or ammonia 
could be detected ; while four other drainage-waters 
were found to contain not above 2 parts, and two others 
severally 4 and 6 parts of potash, in 1,000,000 parts 
of water. 

The facts now stated are corroborated by a series of 
direct and most instructive experiments made by Dr. Fraas, 
to ascertain what substances the rain faUing in the six 



92 



THE SOIL. 



summer months takes up from tlie surface soil and carries 
down into the deeper layers. 

In lysimeters, or underground rain-gauges specially con- 
structed for the purpose, a collection was made of the 
rain-water, which trickled through a layer of earth, 
6 inches deep by 1 square foot in transverse section, from 
the 6th April to the 7th October. The rain-gauge kept 
at a neighbouring observatory indicated, up to the 1st 
October, a fall of rain amounting to 480'7 millimetres 
(18-75 inches).* 

Four lysimeters were filled with the same earth taken 
from the subsoil of the stiff clay at Bogenhausen ; in two 
of them (III. and IV.) the earth was manured with 
2 pounds of cow's dung ; the other two were left un- 
manured. Nos. II. and IV. were sown with barley. 

Calculated upon a square metre (10-75 square feet) of 
ground, the following were found to be the quantities of 
water that had passed through. Dr. Zoeller determined 
the amount of soluble substances contained in the water ; 
the quantities of phosphoric acid and ammonia were too 
small to be appreciable : — 





Lysimeter 


^ I. 

unmannred : 
and without 
vegetation 


II. 

unmanivred : 

sown with. 

barley 


in. 

manured : 
without 
vegetation 


IV. ^ 
mamu-ed : 
sown with 
barley 


Quantity of perco- 
lated water 

Quantity of potash 
contained . 

Or, per hectare, of 
2| acres 


Litres Pints 
218=383-68 

Grams. Grains 
0-516 = 8-0 

Kilogr. lbs. avr. 
5-16 = ll-35 


Litres Pints 
213 = 374-88 

Grams. Grains 
0-434 = 6-7 

Kilogr. lbs. avr. 
4-34 = 9-5 


Litres Pints 
304 = 535 

Grams. Grains 
1-265 = 19-5 

Kilogr. lbs. avr. 
12-65 = 27-8 


Litres Pints 
144=253-5 

Grams. Grains 
0-552 = 8-5 

Kilogr. lbs. avr. 
5-52 = 12-1 



* The lysimeter consisted of a square box, open at the top, closed 
at the bottom ; at a depth of six inches from the open top a sieve -was 
inserted, from whieh, up to the rim, the box was filled with earth. 
The rain falling upon a square foot of surface, and trickling through 



MATTERS DISSOLVED BY RAIN WATER IN SOIL. 93 

In lysimeters I. and II. nearly the same quantities of 
water percolated through the earth ; in the two others 
the difference is great ; the two former alone, therefore, 
admit of comparison as regards the solvent power of the 
water. 

These experiments show that less than one-half of the 
rain falhng on the field under the given conditions, reached 
a depth of 6 inches ; and that, calculating for 1 miUion 
parts of water, the unmanured soils I. and II. gave re- 
spectively 2-37 and 2*03 pounds, the manured soils III. 
and IV. 5-46 and 3*82 pounds of potash. The quantities 
of potash in the manured soils do not exceed the average 
quantity of potash found in drainage-water (Krocker). 

The barley grown in the earth of lysimeter 11. produced, 
per square metre, 137"3 grammes (2120 grains) of barley- 
corns, and 147*9 grammes (2272 grains) of straw, con- 
taining in their ashes (the corns in 2-47 per cent., the 
straw in 4*95 per cent, of ash) : — 

In the corns . . 0"823 grammes 12*6 grains of potash 
„ straw . . 1-410 „ 21-8 „ 



Total . 2-233 „ 34-4 „ „ 

The quantity of potash absorbed by the water from 
the earth in the first lysimeter, which was not sown 
with barley, amounted altogether to 0-516 gramme 
(8-0 grain) ; in the second lysimeter to 0*434 gramme 
(6*7 grains). The difference is 0-082 gramme (1-3 grains). 
If we think ourselves warranted in concludins; from this, 

the six inches of earth, was collected beneath the sieve, in the box. 
The box was buried in an open field, np to the border, so that the 
earth in it was level with the stirface of the field. Two lysimeters were 
filled with lime soils from the. banks of the Isar ; but one of them 
broke, and the water could not be collected : hence the results obtained 
from the other lost their importance as a comparative experiment. 



94 THE SOIL. 

that the duninution in the quantity of potash in the 
water of the second lysimeter resulted from its absorption 
by the roots of the barley, we should be necessarily led to 
infer that the plants received — 

By the agency of the percolating water 0'082 grammes 1"3 grs. 
Direct from the soil . . . 2" 151 ,, 33'2 ,, 



Total . . 2-233 „ 34-5 „ 

and, accordingly, 96*4 per cent, direct from the soil, and 
3-6 per cent, from the water ; that is, 27 times more from 
the former than from the latter. 

Let us now assume, from the results obtained with the 
third lysimeter, which was filled with earth richly 
manured with cow-dung, that the rain-water faUing on a 
surface of one hectare (2^ acres) of land, dissolves, out of 
a layer of arable surface soil 6 inches deep, 12*65 kilo- 
grammes (27*8 lbs.) of potash ; and let us compare with 
this the quantity of potash withdrawn from a hectare of 
ground by a potato or turnip crop. We know that an 
average potato crop from a hectare contains in the 
tubers 204 kilogrammes (449 lbs.) of ash, of which 100 
kilogrammes (220 lbs.) are potash ; and an average 
turnip crop, 572 kilogrammes (1258 lbs.) of ash, of 
which 248 kilogrammes (545 lbs.) are potash ; and we 
easily perceive that, even had the entire amomit of the 
potash dissolved by the rain been conveyed into the 
plants to serve as food, yet this would be sufficient to 
supply, with the necessary potash, only the eighth part of 
the potato tubers and the twentieth part of the turnips 
severally produced on a hectare of land. The amount of 
potash in the percolated water shows the quantity of 
potash which the water could possibly absorb ; and as 
comparatively but a small portion of the percolating 



EFFECT OF DRAINAGE. 95 

water comes in contact with the roots of the plants, and 
can give up potash to them, it is clear that the constituents 
of the solution moving about in the soil have but a very 
trifling share in the process of nutrition, while the absence 
from it of ammonia and phosphoric acid is of itself suffi- 
cient to prove that these materials in the soil cannot 
change their place. The ground must contain a certain 
amount of moisture to be able to furnish food to plants ; 
but it is not necessary for their growth that the water 
should be free to move about. It is well known that 
stagnant water in the soil is injurious to most of the cul- 
tivated plants ; and the favourable effect upon their 
growth produced by draining just depends on this, that 
an outlet is opened to the water moving by the force 
of its own gravity, and the earth is moistened by that 
water only which is retained by capillary attraction. 

If we regard the porous earth as a system of capillary 
tubes, the condition which must render them best suited 
for the growth of plants is unquestionably this, that the 
narrow capillary spaces should be fiUed with water, the 
wide spaces with air, and that aU of them should be 
accessible to the atmosphere. In a moist soil of the kind, 
affording free access to atmospheric air, the absorbent 
root fibres are in most intimate contact with the earthy 
particles ; the outer surface of the root-fibres may here 
be supposed to form the one, the porous earthy particles 
the other waU of a capillary vessel, the connection between 
them being effected by an exceedingly thin layer of water. 
This condition is equally favom-able for the absorption of 
fixed and of gaseous elements of food. If, on a dry day, 
a wheat or barley-plant is cautiously pulled up from a 
loose soil, a cylinder of earthy particles is seen to adhere 
hke a sheath round every root-fibre. It is from these earthy 



96 THE SOIL, 

particles that the plant derives the phosphoric acid, 
potash, siHcic acid, &c., as well as the ammonia. These 
substances are introduced into the plant by means of the 
thin layer of water, the molecules of which are in motion 
only in so far as the roots exercise an attractive power 
upon them. 

From the composition of spring- water, and the water 
of brooks and rivers, every single drop of which has been 
in contact with rocks, or with the soil of forests and fields, 
we see what exceedingly minute quantities of phosphoric 
acid, ammonia, and potash are taken up by water from 
the earth. In the analysis of water taken from six 
different springs, Graham, Miller, and Hofmann found 
no appreciable traces of ammonia and phosphoric acid. 
In the water of Whitley, there was, in 37,000 gallons 
(370,000 pounds English), 1 pound of potash, or 1 kilo- 
gramme in 135 cubic metres : just the same in 38,000 
gallons from the Critchmere spring ; in 32,000 gallons 
from Velwool ; in 145,000 gallons from Hindhead ; in 
55,000 gallons from the Hasford Millbrook ; and in 
17,700 gallons from the spring near Cosford House. The 
water of the Brunthal spring, near Munich, which is used 
for drinking in a large portion of the city, contains no 
ammonia, no phosphoric acid, and in 87,000 pounds, 
1 pound of potash. 

From these and other analyses of spring, well, and 
drainage water, we are not warranted in concluding that 
potash, ammonia, and phosphoric acid are deficient in the 
water of all springs, brooks, and rivers ; on the contrary, 
it is quite certain that the water in many marshes contains 
both potash and phosphoric acid in notable quantities.* 

* Thus a litre (1"7G pints) of water taken from an artificial pond in 
the Botanic Garden at Munich, left a residue of 0"425 gramme 
(G'5 grains), which contained, in 100 parts — 



WHY SALTS AEE FOUND IN STAGNANT POOLS. 



97 



The presence of potash, phosphoric acid, iron, and 
sulphuric acid, in the water of stagnant pools, is easily 
explained. 

Li a stagnant pool or bog are gradually collected the 
remains of dead generations of plants, the roots of which 
have drawn a quantity of mineral matter from a certain 
depth of the soil. These vegetable remains undergo 
decomposition at the bottom of the pools, and their 
inorganic elements, or ash-constituents, are dissolved by 
the aid of carbonic acid, and perhaps also of organic 
acids. They remain dissolved in the water, when the 
surrounding mud and the earth in contact with this 
solution have been completely saturated with them. 

Scherer found in the three wells at Brlickenau all the 
substances contained in the water above-mentioned, of 
the Botanic Garden pond, besides acetic, formic, butyric 
and propionic acids. The mountains all around Brlickenau 
are formed of variegated sandstone (Bunter sandstein) ; 
the vegetation of the whole surrounding country is most 
luxuriant, resembling the primeval forests ; there are 
numerous oak-lands and beech-lands, with trees nearly 
a thousand years old. Hence Scherer is led to attribute 



Lime ...... 


. 35-000 


Magnesia ..... 


. 12-264 


Chloride of sodium 


. 10-100 


Potash ..... 


. 3-970 


Soda ...... 


. 0-471 


Sesqtiioxide of iron with alumina . 


. 0-721 


Phosphoric acid .... 


. 2-619 


Sulphuric acid 


. 8-271 


Silicic acid .... 


. 3-240 


Incombustible constituents 


. 78-656 


Water lost 


. 23-344 




100-000 



H 



98 THE SOIL. 

tlie composition of tlie well-water at Briickenau to the 
solvent action of rain percolating through a humose soil, 
rich in decaying vegetable substances. (' Annal. der Chem. 
und Pharm.' i. c. 285.) 

It is clear that wherever conditions have been at work 
similar to those under which the bog- water in the Botanic 
Garden of Munich and the wells of Briickenau have been 
formed, the water found on the surface of the earth, in 
pools, springs, or brooks, will contain in the most varying 
proportions nutritive elements useful to plants, such as 
phosphoric acid and potash, which are not found m other 
waters. In hke manner, an arable soil rich in vegetable 
remains, in which, from the processes of decay incessantly 
going on, products of an acid character are generated, 
will be able to give up, to the rain-water percolating 
through it, phosphoric acid and alkalies, which are thus 
carried down to the deeper layers, and appear in the 
drainage water. The quantity of these substances dis- 
solved in the water will depend ujDon the condition of the 
soil on which the plants grow, the ash constituents of which 
are carried away by the rain-water, from their decaying 
remains. Where the ground is rocky, covered with a 
thin coating of earth and a thick clothing of foliage, the 
water which runs off will carry down to the lower layers 
all the more fixed elements of vegetable food, in propor- 
tion as the layer of earth itself retains less of them. The 
finer earthy particles of such a soil, washed away by 
heavy rains, are carried down by torrents to the valleys 
and low lands, and form a soil of all degrees of fertihty 
according to their chemical condition, which determines 
their power of absorbing dissolved nutritive substances. 
But these layers of earth formed from the mud borne 
down by the torrents will always either be saturated, or 
graduaUy become saturated with the nutritive substances 



FEETILISING EFFECT OF BOG SOIL AND MUD, 99 

contained in the water, from whicli they are deposited. 
This, perhaps, explains the difference in the fertihsing 
effects of the waters used for irrigating meadows, which 
must necessarily vary very much according to the source 
of the water ; that which has collected on hills covered 
with a rich vegetation, or has been derived from over- 
flowing stagnant pools, will doubtless convey manuring 
matters to the meadow-lands ; whilst water flowing from 
bare mountains cannot, in this particular respect, exert 
any action upon the increase of the grass crop. If such 
increase takes place notwithstanding, the cause must be 
sought elsewhere. 

In many places bog-soil, and the mud from ditches, 
stagnant waters and ponds, are highly esteemed as 
fertilising agents ; and their influence is explained by the 
fact, that their smallest particles are saturated with 
manuring matters, or elements of the food of plants. 
The same remark applies to the fertihty of many tracts 
of cleared wood-land, where the soil for forty or eighty 
years, or even longer, has received from the layer of 
fohage and vegetable remains decaying on it, a certain 
supply of ash-constituents, drawn from a great depth, 
which are retained by the upper layers of the porous soil, 
and serve to enrich it. 

The injury done to wood-lands by raking away the 
leaves cannot be explained merely upon the assumption 
that the soil is deprived of its ash constituents, which are 
taken away with the fohage ; for, in themselves, the fallen 
leaves and twigs are poor in nutritive substances, especially 
potash and phosphoric acid ; and besides, these elements 
do not reach the deeper layers of the soil, where they 
might be again absorbed by the roots. The injury is, 
perhaps, rather attributable to the fact, that the remains of 
leaves and plants constitute a lasting source of carbonic 

H 2 



100 THE SOIL. 

acid, which, carried by rain to tlie deeper layers, must 
powerfully contribute to disintegrate and decompose the 
earthy particles. In a dense wood, where the air is more 
rarely renewed than in the open plain, this supply of 
carbonic acid is important ; moreover, the thick carpet of 
leaves protects the ground from being dried by the air, 
and maintains it in a permanent state of moisture, par- 
ticularly useful to fohaceous trees, which exhale from 
their leaves larger quantities of water than the coniferous 
plants. 

To understand the operations of agriculture, it is indis- 
pensably necessary that the farmer should have the 
clearest knowledge of the manner in which plants derive 
their nutriment from the soil. 

The opinion that the roots of plants extract their food 
immediately from those portions of the soil which are in 
direct contact with their absorbent surfaces, does not 
imply that potash, lime, or phosphate of lime, in the sohd, 
undissolved state can penetrate the membrane of the 
cells ; * nor does it imply that the nutritive substances 

* If a glass vessel is filled to tlie brim witli water, in which are a 
few drops of hydrochloric acid, and covered closely Avith a piece of 
bladder, so that the Avater moistens the bladder and no air is left 
betAveen them, and the outside of the bladder is carefully dried, it 
may then be seen how a solid body, without the cooperation of a fluid 
from the outside, can make its way through the bladder to the Avater in 
the glass. For if a little chalk or finely -pulverised phosphate of hme 
is strewed upon the dried outer surface of the bladder, the poAvder will 
disappear in the course of a few hours, and the usual reactions will 
show the presence of lime and phosphate of lime in the fluid. 

Of course the passage of the carbonate and phosphate of Hme in the 
solid state through the bladder into the Avater, is only apparent. Both 
salts are dissolved in the pores of the membrane where they come in 
contact with the acidulated Avater, and as the evaporation of the Avater 
from the bladder someAvhat diminishes the inner pressure as compared 
to the outer, the stronger outer pressure, assisted by the soh'^ent power 
of the Avater, forces the solution iuAvard. 



MAJS"NER IN WHICH ROOTS TAKE UP FOOD. 101 

held in solution by the water moving about in the soil 
may not, under certain circumstances, be absorbed by the 
roots of the plants. But it is based upon the assumed 
fact, that the roots receive their food from the thin layer 
of water which, retained by capillary attraction, is in 
intimate contact with the earth and with the root surface, 
and not from more remote layers of water ; that between 
the root surface, the layer of water, and the earthy par- 
ticles, a reciprocal action goes on, which does not take 
place between the w^ater and the earthy particles alone. 
It also assumes as probable, that the nutritive substances 
adhering, in a state of exceedingly minute division, to the 
outer surface of the earthy particles, are in direct contact 
with the fluid of the porous absorbent cell-walls, by means 
of a very thin layer of water ; and that the solution of 
the solid elements is effected in the pores of the cell- 
walls, whence they pass immediately into the system of 
the plant. 

The facts in support of this view, briefly recapitulated, 
are as follow : The roots of all land-plants, and of most 
marsh- plants, are in direct contact with the earthy 
particles. These particles of earth have the power of 
attracting the most important elements of food conveyed 
to them in watery solution (such as potash, phosphoric 
acid, silicic acid, ammonia), and of retaining them, just as 
charcoal retains colouring matters. In most cases that 
have been investigated it has been found that the water 
moving about in the ground extracts from the soil 
scarcely any appreciable quantities of ammonia, no phos- 
phoric acid, and potash in such trifling quantities, that all 
these together are quite insufficient to afford the requisite 
supply of these elements to the plants growing in the 
field. 

Water stagnant in the ground, so far from promoting 



102 THE SOIL, 

the absorption of food, injures the growth of land- 
plants. 

If plants really did receive the elements of their food 
from a solution which could change its place in the soil, 
then aU drainage waters, spring, brook, and river waters, 
must contain the principal nutritive substances of all 
plants ; and it must be quite practicable, by continued 
lixiviation, to extract from every arable soil, without dis- 
tinction, all the nutritive substances, either entirely, or 
at least in amount corresponding to the quantity con- 
tained in a crop. But, in reality, this is not practicable. 
By the action of water, the field loses none of the prm- 
cipal conditions of its fertihty, in such a degree as per- 
ceptibly to impair the growth of plants cultivated on it. 

For thousands of years, all fields have been exposed to 
the lixiviating action of rain-water, without losing their 
powers of fertility. In all parts of the earth, where man 
for the first time draws furrows with the plough, he finds 
the arable crust, or top layer of the field, richer and more 
fertile than the subsoil. The fertility of the ground is 
not diminished by plants growing thereon ; not until the 
plants are removed from the ground does it gradually 
lose its fruitfulness. 

The opinion that some cause is at work within the 
plant itself, which seems to render soluble certain ele- 
ments of food, and make them available foi" nutrition, is 
not contradicted by the experiments of Knop, Sachs, and 
Stohmanjst, who have shown that many land-plants, with- 
out touching a particle of earth, may be brought to 
flowering and seed-bearing in water, to which the mmeral 
elements of food have been added. These experiments, 
which have thrown considerable light upon the physiolo- 
gical importance of the several nutritive substances (see 
Appendix E.), merely prove how admirably the ground is 



PLANTS GEOWN IN SOIL AND IN WATER. 103 

adapted to the requirements of plants, and how much 
human ingenuity, knowledge, and minute care, it takes to 
supply, under circumstances cliffermg so widely from the 
natural condition, certain properties of arable soil, which 
insure the healthy growth of plants. 

If the supply of nutritive substances in a state of solu- 
tion were really suited to the nature of the plant and 
the functions of the roots, it would follow that in such a 
solution, most abundantly provided with all the elements 
of food in the most movable form, plants must thrive 
the more luxuriantly the fewer the obstacles are which 
oppose their absorption of food. 

A young rye-plant, placed in a fertile soil, will often 
send forth a bunch of thirty or forty stalks, each of them 
bearing an ear, and will yield a thousandfold crop of 
grains, or even more ; yet this plant draws its mineral food 
from a volume of earth, from which the most persevering 
hxiviation with pure water, or water containing carbonic 
acid, will not extract even the one-hundredth part of the 
phosphoric acid and nitrogen, nor the fiftieth part of 
the potash and the sihcic acid, which the plant has drawn 
from the soil. How is it then possible, under such cir- 
cumstances, to assume that water alone would have suf- 
ficed, by virtue of its solvent power, to render available 
to the plant all the substances found in it ? 

None of the plants grown in watery solutions of the 
mineral elements of their food, even though thriving 
luxuriantly, will bear the remotest comparison, in the bulk 
of vegetable matter produced, with plants gTown in a 
fertile soil ; and the entire process of developement in them 
proves that the conditions of thriving growth in the soil 
are quite of another kind. 

The greatest weight of crop obtained by Stohmann 
from an Indian corn plant grown in water amounted to 



104 THE SOIL. 

84 grammes ; while he ob tamed from another Indian corn 
plant grown in the soil, at the same time and from the 
same seed, a crop weighing 346 grammes. In Knop's 
experiments, the dry weight of two Indian corn plants, 
the one grown in water, the other in the soil, was found 
to be as 1 : 7. 

The water circulating in the soil contains chloride of 
sodium, lime, and magnesia — the two latter in combina- 
tion partly with carbonic acid, partly with mineral acids ; 
and there can hardly be a doubt but that the plant 
absorbs a portion of these substances from the solution. 
The same must apply equally to potash, ammonia, and 
the dissolved phosphates ; but the water circulating in the 
soil, in a normal condition, either does not hold the three 
last-named substances in solution, or not in sufficient 
quantities to supply the demands of the plant. 

According to the ordinary rules of natm-al science, 
when we seek to explain a phenomenon, we leave out of 
view those cases in which the conditions superinducing 
the phenomenon are clear and patent. For instance, if 
we find in bog-water all the ash-constituents of duck- 
weed, there can be no doubt about the form in which 
they passed into the plant ; they were dissolved in water, 
and they were absorbed in a soluble state. Li such a 
case, we have merely to explain the reason why the 
several ash-constituents, being all present in one and the 
same form, have yet passed into the plant in unequal 
proportions. 

If, in another case, we find that the rain-water which 
falls on a given area of land, dissolves out of the soil many 
times more potash than was contained in a crop of turnips 
grown on that area, there is every reason to assume that the 
turnip, like the duckweed, has absorbed the needful potash 
from a solution. But if in the entire quantity of water 



IN WHAT MANNER PLANTS ABSOEB FOOD. 105 

which falls on the field during the period of vegetation, we 
find only just so much potash as the turnip crop requires, 
and no more, the assumption that the potash in the turnips 
has been derived from this solution would necessarily 
involve the impossible supposition, that all the watery 
particles containing potash must have been in contact 
with the roots of the tui-nips ; otherwise, the latter could 
not have absorbed so much potash as is actuaUy found in 
them. This supposition is impossible ; because, during 
the time when the turnip vegetates, there is generally no 
water circulating in the soil — such, for instance, as might 
be carried ofi" by chain-pipes. 

If the examination of the water in the soil shows it to 
contain half the quantity of potash required by a turnip 
crop, there is no need to explain how the dissolved half 
of the potash has passed into the turnip-plant, but in 
what form and manner the plant has absorbed the other 
half deficient in the water. 

If, again, by the examination of the water in other 
fields, we find that it contains only ^ ; nay, only ^, g^, or 
-^jj of the quantity of potash found in a turnip crop grown 
upon it ; and if we further ascertain that in a soil, favour- 
able for the growth of turnips, the plant always takes up 
the same quantity of potash from the ground, no matter 
how much or how little of that substance the water cir- 
culating in the soil dissolves from the earth ; it follows, 
that as the water, the soil, and the plant, can alone come 
into consideration here, the direct power of the water to 
dissolve potash is of no importance to the plant ; and 
that the plant itself, by the help of water, must have ren- 
dered the needful potash soluble. 

What is here asserted of one constituent, holds good 
for all. If, therefore, we find, that by treating a soil with 
rain-water we can dissolve from it potash, phosphoric 



106 THE SOIL. 

acid, and ammonia or nitric acid, in sufficient quantity to 
account for the presence of these substances in the 
cereal plants grown on such a soil ; while, on the other 
hand, we find that the plant contains a hundred times 
more silicic acid than the water could possibly have sup- 
phed ; the cause of the absorption of silicic acid, which 
clearly is not in the water, must again here be sought for 
in the plant itself. Again, if other cases show that an 
equally abundant crop of corn is obtained on fields, from 
which water fails to extract phosphoric acid or ammonia, 
here, too, we are led to the conclusion that the nutritive 
substances dissolved in the water are of no special import- 
ance to the plants in question ; but that, as an indispen- 
sable requisite, these elements must possess the form most 
suitable for the action of the root, be this what it may. 

The beautiful experiments on vegetation made con- 
jointly by Professor I^Tageh and Dr. Zoeller, in the Botanic 
Garden at Munich, most strikingly prove the correctness 
of the conclusions to which the analysis of drainage and 
other waters has led. Instead of growing plants in 
solutions of the mineral elements of their food, as had 
been done in all previous experiments, they pursued the 
very opposite course ; they placed the seeds of the plants 
in a soil containing all the elements of their food m an 
insoluble state. 

In such experiments, it is not easy to find a mate- 
rial which can be used as a substitute for arable soil, 
and possessing all its properties ; and the difficulty is 
proved by the fact, that none of the plants grown by 
Boussingault and others, in an artificial soil, abundantly 
provided with all the elements of food, could even 
remotely bear comparison with a plant grown in a fertile 
arable soil. Pulverised charcoal or pumice-stone have 
the power of extracting many elements of the food of 



ABSORPTIVE POWER OP TURF. 107 

plants from their solutions, and physically fixing them ; 
but they have not, in the moist state, that soft, plastic, 
and yielding condition of the clay in arable soil, which 
permits the intimate contact of the roots with the earthy 
particles. The best substitute for the purpose is coarsely- 
powdered turf, which, in the moist state, forms a plastic 
mass, bearing a remote resemblance to clay, and, like 
arable soil, absorbs all elements of the food of plants from 
their solutions. Accordingly, Nageli and Zoeller used in 
their experiments coarsely-powdered turf as the vehicle 
of the nutritive substances, after having ascertained its 
absorptive power for the several elements of food. 

A litre (1*76 pint) of turf, weighing 324 grammes 
(4987-6 grs.), was found to absorb from solutions of 
carbonate of potash, carbonate of ammonia, carbonate of 
soda, and phosphate of lime — 1*45 grammes (22*4 grs.) 
of potash, 1*227 grammes (19 grs.) of ammonia, 0-205 
gramme (3-2 grs.) of soda, and 0-890 gramme (13-7 grs.) 
of phosphate of lime equal to 0-410 gramme (6-3 grs.) 
of phosphoric acid. 

The quantities of potash and ammonia here given do 
not show the total amounts of these substances which the 
turf will absorb to the point of complete saturation, but 
merely what it will take up when simply mixed with the 
solutions, and left in contact with them for a few hours. 
If we add more of these solutions to the turf-powder, the 
fluid exhibits an alkahne reaction, which disappears again 
after one or more days ; and it is only at the end of 
eight days, when the litre (1-76 pint) of turf has taken 
up 7*892 grammes (121*6 grs.) of potash and 4*169 
grammes (64*2 grs.) of ammonia, that the alkaline re- 
action remains permanent. What we shall hereafter 
designate as saturated turf contains only i of the potash 
and -^ of the ammonia, which v/ould be absorbed by that 
substance to the point of complete saturation. 



108 



THE SOIL. 



To represent different soils, containing various propor- 
tions of nutritive substances, three mixtures were made 
of saturated and ordinary turf-powder : — 

1 mixture contained 1 vol. of saturated turf-powder, 



and 1 vol. of diy tiirf-powder 
3 



These mixtures represented different kinds of earth, in 
each vohime of which the third contained one-fourth, the 
second one-half the quantity of the nutritive substances 
present in the first. 

The pure turf contained 2-5 per cent, of nitrogen, and 
100 grammes yielded 4-4 grammes of ash, which, upon 
analysis, were found to contain 0T15 gramme of potash, 
0-0576 gramme of phosphoric acid, besides lime, sesqui- 
oxide of iron, sihcic acid, magnesia, sulphuric acid, and 
soda. (See more fully in Appendix E.) 

With each of these mixtures a pot was filled, each pot 
holding 8^ litres (2592 grammes, = 39917 grs.) ; a 
fourth pot, of similar size, contained dry turf-powder. 

Takino; into consideration the amount of ash in 
ordinary turf, the four pots severally contained the 
following quantities of nutritive substances : — 



Nitrogen . 
Potash . 
Phosphoric 
acid 


1st Pot 

witli common 

turf 


2nd Pot 

quarter saturated 

turf 


3rd Pot 

half satm-ated 

tiu-f 


4th Pot 

fully satm-ated 

tm-f 


Grams. Grains 

71- =1093-5 

3-18 = 49-0 

1-586= 24-4 


Grams. Grains 
2-60 =40-0 
3-075 = 47-4 

0-83 =12-8 


Grams. Grains 
4-32 = 66-5 
6-15 = 94-7 

1-75 = 27-0 


Grams. Grains 

8-65 = 133-2 

12-30 = 189-5 

3-49= 53-8 



The figures showing the quantities of nitrogen, potash, 
and phosphoric acid, express the amount of nitrogen in 
the dry turf (in the first pot), and the amount of potash 
and phosphoric acid in its ash. For the other pots, the 
figures express the quantity of nutritive substances which 
had been added. 



GEOWTH OF BEANS IN EXPERIMENTAL SOIL. 



109 



In each of these pots, five dwarf-beans were planted, 
the weight of which had been carefuUy determined, and 
which had been allowed to germinate in pure water. 

The plants in the three manured pots grew very evenly, 
and the luxuriance of their growth excited the astonish- 
ment of all who saw them. 

During the first month, the plants in pots 2 and 3 
(filled respectively with turf ^ and -^ saturated) presented 
a finer appearance than the others ; but those m pot 4 
(filled with saturated turf) soon overtook them ; and the 
difference, in the size of the leaves, in proportion to the 
greater richness of the soil, was very striking. 

Eemarkable, too, was the influence of the soil upon 
the term of the vegetating period. Each of the five 
plants in the pure turf produced a small pod, and, to- 
gether, the five pods contained 14 seeds. During the 
ripening of the seeds, the leaves died from below 
upwards ; so that, before the pods had turned yellow, all 
the leaves had fallen off. The plants in the saturated 
turf remained green longer than any of the others, and 
their seeds ripened latest. The last pod of these plants 
was cropped on July 29, whilst the last pod of the plants 
in the pure turf had already been cropped on July 16. 

The following table shows the crops yielded by all four 
pots, with the number and weight of the seeds : — 



Number gathered . 


1st Pot 
pure 
tarf 


2nd Pot 

turf quarter 

saturated 


3rd Pot 
turf half 
saturated 


4th Pot 
turf fully- 
saturated 


Beans 
14 


Beans 
79 


Beans 
80 


Beans 
103 


,, sown 


5 


5 

Weight in 


5 

Grammes 


5 


Gathered 
Sown . 


Grammes 

7-9 
3-965 


Grammes 
56-7 
3-88 


Grammes 
74-3 
4-087 


Grammes 
105- 
4-055 


Excess of crop over 
seed . 


3-9 


52-82 


70-213 


100-945 



110 



THE SOIL. 



What strikes us here at once is the great difference in 
the number and weight of the seeds respectively gathered 
from the several pots. The soil richer in nutritive sub- 
stances yielded not only more, but larger and heavier 
seeds, the average weight in milligrammes being respect- 
ively : — 



One seed-bean weighed 

One of the gathered beans weighed 


1st Pot 


2ncl Pot 


3rd Pot 


4th Pot 


milligr. 
793 
564 


milligr. 
776 
718 


milligr. 
817 
917 


milligr. 

813 

1019 



Of the seeds of the plants grown in the first pot (pure 
turf), seven weighed no more than five of the beans 
origmally sown ; whereas those of the plants grown in 
the saturated turf weighed each l-5th more than one of 
the seed-beans. 

If we compare the crop of seeds with the quantity of 
nutritive substances contained in the turf of the four pots, 
we see at once what influence the form and distribution 
of the nutritive substances have exercised upon their 
nutritive power. 

The 1-4 th saturated turf contained a little above one- 
half (0-83 gramme) more phosphoric acid than that in 
the pure turf (1-586 grammes) ; the potash was doubled ; 
and the amount of nitrogen was increased only by gyth. 
The crop, however, exceeded that obtained from the 
plants grown in pure turf, not by ^vd (corresponding to 
the quantity of phosphoric acid added), but it was thirteen 
times as large. The feeble manuring had caused the turf 
in the second pot to render thirteen times more nutritive 
matter for the formation of seed alone, and for the entire 
plants about thuly times more than the pure turf. 

It is evident that only a small proportion of the ash- 
constituents in the pure turf were present in a form suit- 



EELATION OF CEOP TO FOOD IN SOIL. 



Ill 



able for the nutrition of the bean-plant. They conld not 
be absorbed, because they were in chemical combination 
in the substance of the turf. To use a somewhat imper- 
fect figure, the nutritive elements hi the pure turf may be 
imagined to be smTOunded by the turfy substance, which 
hmders theu" contact with the roots ; while in the satu- 
rated turf these elements form the outer coating of the 
turfy substance. 

The crops of seeds show further that they were not in 
proportion to the nutritive substances contained in the 
soil, but that the poorer mixture yielded far more seeds 
than it should have done in proportion to the production 
of the richer mixtures. The proportions in the several 
mixtures were as follows : — 



Amount of manure 

Crop gathered, as . . . 


2ud Pot 
quarter 
saturated 


3rd Pot 
half saturated 


4tliPot 
fully satiu-ated 


1 
2 


2 
2-8 


4 
4 



It is not difficult to understand why this should be so. 
The fact that the ^-saturated turf yielded twice as much 
crop as corresponded to the amount of manure, proves 
that the absorbent root-surface had come in contact with 
double the number of nutritive turf particles. According 
to weight, the ^-saturated turf contained, in every cubic 
centimetre, only Jth of the nutritive substances found in 
the completely saturated turf ; but, by mixing 1 volume 
of saturated with 3 volumes of unsaturated turf, the 
former had become far more distributed, and its volume 
or efficient surface had been made larger. Supposing it 
were possible to coat 3 volumes of ordinary turf-powder 
with 1 volume of saturated, so as completely to surround 
every fragment of the former with saturated turf particles, 
the bean-plants would, in a soil so prepared, grow as 



112 THE SOIL. 

luxuriantly as if every particle of the turf were tliorouglily 
saturated with nutritive substances. 

Hence, the higher produce obtained from the compara- 
tively poorer soil proves that it is only the surface of the 
soil, containing the nutritive elements, which is effective ; 
that the fertility of a soil is not proportionate to the 
quantity of nutritive substances which chemical analysis 
proves to be present ; and lastly, these facts show that it 
is not water which, by virtue of its solvent power, has 
made the nutritive elements available to the roots. 

We know by experiment, that when water has dissolved 
from a saturated soil a certain quantity of ammonia, pot- 
ash, &c., the same amount of water wiU not further 
dissolve from a half-saturated soil (or a soil from which 
one-half of the absorbed potash and ammonia has already 
been extracted) half so much as from the saturated soil ; 
but that the earth, in proportion as it has thus become 
poorer in nutritive substances, will all the more firmly 
retain the residue of the ingredients absorbed by it. 

In the half-saturated turf the nutritive elenients are 
much more firmly bound than in the fully saturated ; 
and, again, in the quarter-saturated much more firmly 
than in the half-saturated. 

Hence, even if the water had been able to dissolve and 
convey to the roots half as much from the half-saturated 
as from the fully saturated, and half as much from the 
quarter-saturated as from the half-saturated, still the 
produce could not in any case be greater than in propor- 
tion to the amount of nutritive substances in the ^oil. 
But, in fact, tliey were far greater, and the roots actually 
absorbed more nutritive substances than the water could 
possibly have conveyed to them, even under the most 
favourable circumstances. 

These experiments have, for the first time, afforded 



FIXED STATE OF FOOD OF PLANTS IN THE SOIL. 113 

direct proof that plants possess the power of absorbing 
their necessary nutritive elements from a soil in which 
they are present in physical combination, i.e. in a 
state wherein they have lost their solubihty in water; 
and the comportment of arable and cultivated soil in 
general shows that the nutritive substances contained in 
them must be present in the same form as in the artificial 
turf soil of these experiments, with this difference, how- 
ever, that the earthy particles in the arable soil are not 
merely the vehicles of these substances, but their source. 
In a soil consisting of turf-powder, a second crop will not 
succeed so well as the first, unless the nutritive sub- 
stances which have been removed are again supplied ; 
nor will the soil regain its fertility, however long it be 
left fallow. 

The benefit derived from mechanical tillage of the 
ground depends upon the law, that the nutritive substances 
existino- in a fruitful soil are not made to chano-e their 
place by the water circulating in it ; that the cultivated 
plants receive their food principally from the earthy 
particles with which the roots are in direct contact, out 
of a solution forming around the roots themselves ; and 
that all nutritive substances lying beyond the immediate 
reach of the roots, though in themselves quite effective as 
food, are not directly available for the use of the plants. 

There are no isolated laws in nature, but they are 
all together links in one chain of laws, which are in tm-n 
subordinate to a higher and a highest law. 

With the natural law, that organic life is developed 
only in the outermost crust of the earth which is exposed 
to the sun, is most intimately connected the power of the 
fragments of that crust which form the arable surface soil, 
to collect and retain all those nutritive substances on 
which hfe depends. A plant is not, like an animal, 



114 THE SOIL. 

endowed with special organs to dissolve the food and 
make it ready for absorption ; this preparation of the 
nutriment is assigned by another law to the fruitful earth 
itself, which in this respect discharges the functions per- 
formed by the stomach and intestines of animals. The 
arable soil decomposes all salts of potash, of ammonia, and 
the soluble phosphates ; and the potash, ammonia, and 
phosphoric acid always take the same form in the soil, no 
matter from what salt they are derived. In performing 
this function, the plant-bearing earth constitutes for the 
use of man and beast an immense purifying apparatus, 
whereby it removes from the water all matters hurtful to 
the health of animals, and all products resulting from the 
decay and putrefaction of deceased generations of plants 
and animals. 

The question how much of the several nutritive sub- 
stances a soil must contain to yield remunerative crops is 
of great importance, but its exact determination is beset 
with vast difficulties. If, indeed, the nutritive power of 
an arable soil depends upon the quantity of substances 
held in physical combination in the ground, it is evident 
that a chemical analysis, which cannot rigorously distm- 
guish elements in chemical combination from those in 
physical combination, must fail to afford any certain 
conclusion in tlie matter. 

In comparing several equally productive soils, we often 
find that they differ immensely in their chemical com- 
position ; and that of two soils containmg, the one 80 to 
90 per cent,, the other only 20 per cent, of pebbles and 
sand, the former will frequently yield better crops than 
the latter. The case is possible, that a soil fruitful in itself 
may not suffer any diminution of its fertility by being 
mixed with half its volume of sand, but may actuaUy 
become more productive, though it now contains, in every 



WHY RYE MAY FLOURISH AND NOT WHEAT. 115 

part of its transverse section, one- third less nutritive matter 
than before. The reason is, that by the addition of sand 
the food-aflfording surface of the other constituent parts 
of the soil is enlarged, and on this everything depends as 
regards the power of the soil to give up to plants the food 
contained in it. 

A soil on which rye thrives well often proves unsuited 
for the profitable cultivation of wheat, though both plants 
take from the soil exactly the same constituents. 

It is clear that the failure of wheat on such a soil arises 
from this cause, that the wheat plants, ^vithin the allotted 
period of their existence, do not find nutriment enough 
for their full developemeiit in the food-supplying soil 
about their roots, whilst the quantity supphed is ample for 
the rye plants. 

Now chemical analysis proves that such a rye soil alto- 
gether contains, to a depth of 5 to 10 inches, fifty — nay, a 
hundred times more of the food-elements of the wheat 
plant than would be required for an abundant crop of 
wheat ; and yet, in spite of this superabundance, the field 
will aiford no remunerative crop to the agriculturist. 

If we compare the quantities of phosphoric acid and 
potash drawn from an area of 2^ acres (hectare), by an 
average wheat crop (2000 kilogrammes = 4400 lbs. of 
grain, and 5000 kilogrammes =11000 lbs. of straw) and 
a rye crop (1600 kilogrammes = 3520 lbs. of grain and 
3800 kilogrammes =8360 lbs. of straw), we find that the 
two crops severally received from the soil — 



Phosphoric acid . 

Potash 

Silicic acid . 


Wheat 


Rye 


Kilogr. lbs. lbs. 
25—26= 55 to 57 
52 = 114 
160 = 352 


Kilogr. lbs. lbs. 

17— 18= 37 to 39 

39— 40= 86— 88 

100—110 = 220—242 



I 2 



116 THE SOIL. 

The difference in the absolute requirement is therefore 
very small. The wheat crop received from the soil only 
9 kilogrammes (= 20 lbs.) of phosphoric acid, about 12 
kilogrammes ( = 26*4 lbs.) of potash, and 50 to 60 kilo- 
grammes ( = 110 to 132 lbs.) of sihcic acid, more than the 
rye crop. 

Before the true cause was known upon which the nutri- 
tive power of arable soil depends, it was utterly incom- 
prehensible how this trifling difference of a few pounds of 
phosphoric acid, sihcic acid, and potash in the requirements 
of wheat and rye, could make so great a difference in the 
quality of a field ; for in comparison with the total amount 
of these ingredients actually contained in the rye field, 
the additional quantity required by the wheat plant is 
inappreciably small. 

This difference would indeed be inconceivable if the 
nutritive substances required by the cereal plants had 
any perceptible power of locomotion, for in that case there 
could not be an actual deficiency of food in any given spot 
of the soil ; every fall of rain would provide the poorer 
places Avith nutriment, if the trifling excess required by 
the wheat above the rye could really be distributed by 
the agency of water. 

Thus, although a soil suited for rye but not for wheat, 
may contain, within a short distance from the roots of the 
wheat, a large quantity of phosphoric acid and potash, 
often amounting, in the volume of earth between two rye 
plants, to fifty times more than the trifling addition de- 
manded by the wheat, yet, in point of fact, this nutriment 
cannot reach the roots of the latter. 

But if we consider that the nutritive substances cannot 
of themselves change their place in the ground, the failure 
of wheat upon a rye field is very simply explained. 

If a 2^ acre held yields to an average rye crop (grain 



I^ATURE OP A WHEAT SOIL. 117 

and straw) 17 million milligrammes (= 37 •41bs.) of phos- 
phoric acid, 39 million milligrammes (=85-8 lbs.) of 
potash, and 102 million milligrammes (=224*4 grains) 
of silicic acid, then the rye plants growing on a square 
decimetre (=15-3 square inches) receive from the soil 17 
milligrammes (=0*26 grains) of phosphoric acid, 39 milli- 
grammes (=0-6 grain) of potash, and 102 milligrammes 
(^1-56 grains) of silicic acid. 

Now, from the same area of a good wheat soil, the 
wheat plants growing on it receive 26 milligrammes of 
phosphoric acid, 52 milligrammes of potash, and 160 mil- 
hgrammes of sihcic acid. The food-absorbent surface of 
the rye and wheat plants is not in contact with all the 
earthy particles which contain food in a square decimetre 
of the field downwards, but only with a small volume of 
the soil ; and it is quite evident, that if the seed is to 
thrive in every spot, the earthy particles, which do not 
happen to come in contact with the roots, must contain 
as much nutritive matter as the others. 

If we could ascertain with any certainty the root- 
surface which absorbs nutriment, we might infer the 
volume of earth from which it received food, for every 
root-fibre is surrounded by a cylinder of earth, the inner 
wall of which facing the root is as it were gnawed off by 
the extremities of the root which press downwards, or by 
the cell-surfaces which are deposited in a downward 
direction. But in no plant are the diameter and length 
of the root-fibres determined, and we must rest satisfied 
with an approximative estimation. 

Let us assume that the 17 milhgrammes (= 0-26 gr.) 
of phosphoric acid, 39 milligrammes (=0-6 gr.) of 
potash, and 102 milligrammes (= 1'56 grs.) of silicic 
acid, are absorbed from a mass of earth the transverse 
section of which is 100 square millimetres (=15 "3 square 



118 THE SOIL. 

inches), then the rye-field m each square dechnetre (1 0,000 
square milhmetres) will contain 1700 milligrammes 
(= 26-2 grs.) of phosphoric acid, 3900 milhgrammes 
(= 60 grs.) of potash, and 10,200 milligrammes (= 15-7 
grs.) of sihcic acid ; that is, a hundred times as much as 
an average rye crop requires. Now, as the wheat plant, 
to thrive equally well, must receive half as much again of 
phosphoric and sihcic acid, and 0-4 more potash, from the 
same portions of the soil, it follows that if a hectare 
(2 J acres), to produce an average rye crop, contams 

1700 kilogrammes= 3740 lbs. of pliosplioric acid, 
3900 „ = 8580 „ potash, and 

10200 „ =22440 „ silicic acid, 

a fertile wheat soil must contain 

2560 kilogrammes= 5632 lbs. of pliosplioric acid, 
5200 „ =11440,, potash, and 

15300 „ =33660 „ silicic acid. 

If a cubic decimetre (1 litre = 1*7 pint) of arable 
soil weighs on an average 1200 grammes (= 2-64 lbs.), 
and we assume that the greater number of the roots of a 
wheat plant do not go deeper than 25 centimetres (10 
inches), then the above 1700 milhgrammes of phosphoric 
acid, 3900 milhgrammes of potash, and 10,200 milh- 
grammes of sihcic acid, must be contained in an available 
form in 2 J cubic decimetres, or 3000 grammes (= QQ lbs.) 
of soil : this makes 0-056 per cent, of phosphoric acid, 
0-034 per cent, of potash, and 0-34 per cent, of silicic 
acid. 

Before we discuss the inferences which foUow from 
these numbers, we must remember that they involve 
some hypothetical elements, which ought not to be left 
out of view. The numbers representing the quantity of 
ash constituents, which an average rye and wheat crop 
take from a hectare (2^ acres) in corn and straw, have 



ESTIMATION OF FOOD IN A WHEAT SOIL. 119 

been determined by chemical analysis, and are not lij^o- 
thetical. It is therefore certain that a wheat crop draws 
from the ground half as much again of phosphoric acid 
and sihcic acid, and one- third more potash, than a rye 
crop. 

The supposition that a wheat soil, to the depth of 10 
inches, contains in physical combination 0'056 per cent, 
of phosphoric acid, 0-034 per cent, of potash, and 0"34 
per cent, of sihcic acid, which makes a hundred times as 
much as a wheat crop would take in corn and straw from 
the field, is purely hypothetical ; and the present question 
is to determine the limits up to which this estimate may 
be accepted as true. 

If arable soil is left for twenty-four hours in contact 
with cold muriatic acid, a certain quantity of potash, 
phosphoric acid, silicic acid, as well as lime, magnesia, &c, 
is extracted. If the soil is treated for a long time with 
boiling muriatic acid, the quantities of dissolved sihcic 
acid and potash are much greater. Lastly, by decom- 
posing by fusion the silicates, and then treating with hot 
muriatic acid, we can obtain all the potash and sihcic 
acid contained in the soil. Without risk of error we may 
assume that those nutritive substances which can be ex- 
tracted by cold muriatic acid are most feebly retained by 
the soil, and approach nearest the elements in physical 
combination ; or, at all events, so near, that by the 
common disintegrating agencies they very easily pass into 
this form of combination. 

In this way Dr. Zoeller subjected to analysis two 
kinds of wheat soil — the loam of Bogenhausen and of 
Weihenstephan, the latter of which in particular repre- 
sents an excellent wheat soil. One hundred parts of 
these two soils yielded to cold muriatic acid — 



120 



THE SOIL. 



Soil of Weihenstephan 
Soil of Bogenhaiisen . 


Phosplioric acid 


Potasli 


Silicic acid 


0-219 
0-129 


0-249 
0-093 


0-596 
0-674 



If these quantities of nutritive elements are present in 
an available condition in these soils, that of Weihen- 
stephan would contain of phosphoric acid almost 400 
times, of potash 700 times, and of sihcic acid rather 
more than 190 times, as much as a wheat crop requires : 
in the soil of Bogenhausen the amount of phosphoric 
acid, potash, and silicic acid would be twice as large as 
the hypothesis presupposed. 

The well-known analyses of similar soils by other 
chemists show that the assumed estimate of the nutritive 
substances required in a good wheat or rye soil is rather 
below than above the actual amount ; and, in fact, the 
future prospects of agriculture would be very gloomy, if 
the ground was not far richer in nutritive substances than 
has here been hypothetically assumed. 

This is, perhaps, the place to state the distinction 
between the fertility of a field and its productive powers. 
According to the experiments of ISTageh and Zoeller, men- 
tioned above, turf may be so saturated with the necessary 
nutritive substances as to become an extremely fruitful 
soil for beans ; and a comparison of the ash constituents, 
in the stalks and seeds of the crop, with the quantity 
which had been added to the turf, shows that the twelve 
to fourteen-fold quantity of these ash constituents was 
enough to produce a very abundant seed crop. The 
porous turf, saturated even in its minutest particles with 
nutritive elements, favoured in this case an enormous de- 
velopement of the roots, to which the largeness of the 
crops is due. Nothing can be more certain than that its 
power of production measured by time is very small, and 



NATUEE OF A EYE SOIL. 121 

that after a very few harvests its fertility would vanish 
speedily and for ever. 

That our corn fields should contain nutritive substances 
in very great abundance is the necessary condition for a 
continuance of good crops, but it is not indispensable for 
one rich harvest. 

A good rye soil is one which produces an average rye 
crop, but less than an average wheat crop. 

From what we have seen, the reason why a wheat 
plant, which requires from the soil the same elements as 
the rye plant, will not thrive as well as the latter upon a 
rye soil, is founded on this, that during the same period 
of time the wheat needs more of these nutritive sub- 
stances than the rye, but cannot obtain this additional 
quantity. Hence, a good wheat soil which yields an 
average wheat crop, differs from a good rye soil which 
produces an average rye crop, inasmuch as the wheat soil 
in all its parts contains more nutritive substances, just in 
proportion as the wheat crop needs and carries away 
more than the rye crop. 

A good rye soil, which is able to give and does give 
1 per cent, of its nutritive substances to an average rye 
crop, would necessarily yield an average wheat crop, if 
the wheat plants growing upon it could extract 1| per 
cent, of its nutriment. But, in fact, this does not 
take place : whence it follows that the absorbent root- 
surfaces of the wheat cannot be half as large again as 
those of the rye ; for, were this the case, the roots of the 
wheat would come into contact with half as many more 
earthy particles yielding nutriment, i. e. the rye soil would 
necessarily produce an average wheat crop, which however 
is not the case. 

The comparative returns, in corn and straw, from a 
rye soil, which has been sown simultaneously half with 



122 THE SOIL. 

wheat and half with rye, might therefore enable us to 
estimate the extent of root surface in wheat and rye 
plants. If the wheat crop from one-half of such a field, 
reckoning by the hectare, receives as much phosphoric 
acid and potash as the rye crop from the other half (17 
kilogrammes of phosphoric acid and 39 kilogrammes of 
potash), this would argue that the roots of the wheat 
have come in contact with earth yielding as much nutri- 
tive substance, and the earth with the same extent of 
absorbent root surfaces, as in the case of the rye. If the 
wheat crop contains phosphoric acid, potash, and silicic 
acid, either more or less than the rye crop, this would 
lead us to infer a larger or smaller ramification of the 
roots. Experiments of this kind with rye, wheat, barley, 
and oats are well worth making, although they have no 
practical interest for the farmer, but merely a physiolo- 
gical importance, and would finally lead to conclusions, 
the correctness of which lies within rather wide limits. ' 
The absorptive power of the plant, and the time of ab- 
sorption, make a difference which, however, hereby 
becomes perceptible. 

Of two plants, with the same absorbent root surface, 
and yielding equal produce, one of which flowers and 
ripens earlier than the other, the one with the shorter 
period of vegetation must find somewhat more food, in 
all the places which furnish its nutriment, in order to 
receive the same amount as the other, which has a longer 
time for absorption. 

Thus, the only hypothetical assumptions in determining 
the above numbers are, that the food-absorbent root 
sm-faces of rye and wheat are equal, and that the rye soil 
yields neither more nor less than exactly 1 per cent, of 
its nutritive substances. No doubt such a soil has no 
actual existence ; but, supposing that we had such a soil 



CONVEESION OP EYE INTO WHEAT SOIL. 



123 



before us, and were to put the question how much nutri- 
ment we must add to convert it into a permanently pro- 
ductive wheat soil, the answer would be not hypothetical, 
but perfectly trustworthy and exact. If 



The wheat soil contains 

The rye soil .... 

The wheat soil is the richer of the 
two by .... . 


Phosphoric acid 


Potash 


Silicic acid 


Kilogr. 
2560 
1700 



860 


Kilogr. 
5200 
3900 

1300 


Kilogr. 
15300 
10200 

5100 



Hence, to a rye soil of a given condition and productive 
power, we should have to add, in some form or other, 
one-half more phosphoric and silicic acid, and one-third 
more potash, than it already contains, to make it capable 
of producmg average crops of wheat grain and straw. 

And to obtain permanently from a wheat soil a crop 
half as large again as an average harvest, we should add 
one- half more of nutritive substances than it already 
contains. 



A hectare of wheat soil contains . 
One-half more .... 


Phosphoric acid 


Potash 


Silicic acid 


Kilogr. 
2560 
1280 

3840 


Kilogr. 
5200 
2600 

3800 


Kilogr. 

10200 

5100 


15300 



These speculations have no other object than to show 
that a small difference in the absolute quantity of a nutri- 
tive element, required by one kind of plant more than 
by another, presupposes a great excess in the amount of 
this constituent in the soil. A wheat crop takes from 
the soil, per hectare (2 J acres), only 8 '6 kilogrammes 
(19 lbs.) more phosphoric acid than a rye crop ; but that 



124 THE SOIL. 

the wheat-roots may appropriate these 8-6 kilogrammes, 
the soil must contain a hundred times as much (860 
kilogrammes) of phosphoric acid as the rye soil, or per- 
haps even more. 

Although these figures refer to an ideal soil of strictly 
definite composition, yet the conclusion which we draw 
is true for all classes of soil. 

It is an undoubted fact, that the ground must always, 
and under all circumstances, contain a larger amount of 
nutritive substances than the crop grown on it. Sup- 
posing the soil to contain, instead of the hundred-fold, 
only the seventy or fifty-fold quantity of the nutritive 
elements in the crop, we infer from the law of the immo- 
bility of these elements, that, to double the crop, we 
must add to the field seventy or fifty times the quantity 
of mineral constituents contained in the produce. In 
practice the case is different, for no actual field, like our 
ideal one, contains phosphoric acid, potash, and silicic 
acid in exactly the relative proportions in which they 
exist in the ash of rye or wheat. Most fields which are 
suitable for cereals are fruitful also for potatoes, clover, 
or turnips, which extract from the soil much more potash 
than the cereals. 

Therefore, to convert a rje soil containing more than 
3900 kilogrammes of potash, per hectare (2-J acres), into 
a wheat soil, would not require an addition of 1300 
kilogrammes of potash, but a proportionately less amount 
would fully answer the purpose. 

We shall hereafter discuss at greater length the rela- 
tions existing between the composition of a soil and its 
fertility. The main conclusion, which the above figures 
are intended to illustrate, is the practical impossil^ility of 
converting a rye soil into a wheat soil by supplying the 
deficient ash constituents, or of making a wheat field by 



PEODUCTIVE POWEE OP EACH SOIL VARIES. 125 

the same means produce half as much again as an average 
crop. Admitting this might be readily accomphshed, 
experimentally, on a small area, yet the price of phos- 
phoric acid, potash, or even of soluble sihca, and the 
impossibihty of procuring them for a large number of 
fields, though in a given field only one of these sub- 
stances had to be increased m the proportion stated, 
would oppose insuperable obstacles to the conversion or 
improvement of land. 

The law of the immobility of the mineral elements in 
the soil explains the agricultural experience of ages, that 
almost universally, under like climatic conditions, certain 
fields are suited for certain plants only, and that no plant 
can be profitably cultivated upon a soil, unless the mineral 
contents of the soil are in proportion to the special re- 
quirements of that plant. 

In practice, it is quite impossible, by a supply of mmeral 
substances, to improve the land of an entke country, so 
that it shall yield crops considerably more abundant than 
the natural store of food elements in the soil enables it to 
produce. 

Every field has a real and an ideal maximum of pro- 
ductive power corresponding to the nutritive substances 
which it contains. Under the most favourable cosmical 
conditions, the real maximum corresponds to that portion 
of the total amount of nutritive elements, which is present 
in the soil in an available form, i. e. in a state of physical 
combination with the soil ; the ideal maximum is what 
might possibly be obtained if the rest of the nutritive sub- 
stances, which are in chemical combination, were con- 
verted into an available form, and distributed through 
the soil. 

Hence, the art of the agriculturist mainly consists in 
selecting such plants as will thrive best on his land, in 



126 THE SOIL. 

adopting a proper system of rotation, and in using all the 
means at his command to make the nutritive elements in 
chemical combination available for plants. 

The achievements of practical agriculture in these re- 
spects are wonderful, and they demonstrate that the 
triumphs of art far exceed those of science, and that the 
farmer, by aiding the agencies which improve the chemical 
and physical condition of his land, can obtain much more 
abundant crops than by supplying nutritive matters. Be- 
cause, what he can supply in the shape of manure, with 
due regard to a proper return, is so small in comparison 
with the store of nutritive matter contained in a fruitful 
soil, that a perceptible increase of produce can hardly be 
expected to result from it. 

But what the farmer may achieve by manuring is at 
best the result — unquestionably a most important one — 
that his crops suffer no diminution. Where they actually 
increase, this is less attributable to the addition made to 
the store of mineral constituents than to their distribution, 
and to the fact that certain quantities of inoperative sub- 
stances have been rendered available. 

If we wished, by increasing the phosphoric acid re- 
quired for the formation of seed, to enable a wheat field 
yielding an average produce of six grains to give two 
additional grains, it would be necessary to increase by ^rd 
the whole amount of the phosphoric acid present in the 
field, and serving for the formation of seed. Eor it is 
always but a smaU fraction of the total quantity supplied 
that comes into contact with the roots of the plants ; and 
that they may be able to absorb this -^rd more, it is indis- 
pensably necessary to increase the phosphoric acid by ^rd 
in all portions of the soil. This reflection explains the 
rule found true in experience, that to produce a marked 
effect upon crops by manuring, a mass of manure must 



RELATION'S EXISTING AMONG FOOD ELEMENTS. 127 

be laid on, utterly disproportionate to the expected in- 
crease. 

A manure will exercise its beneficial action upon a field 
in the most marked manner, when it establishes a more 
suitable relative proportion between the several mineral 
constituents in the soil ; because upon this proportion the 
crops are dependent. No special argument is needed to 
demonstrate, that where a wheat soil contains just so much 
phosphoric acid and potash as will suffice to afford the 
quantity of these two substances required for a fuU wheat 
crop, and no more (accordingly for every part by weight 
of phosphoric acid two parts by weight of potash), an ad- 
ditional supply of one-half more, or even of double the 
quantity of potash, cannot exercise the shghtest possible 
influence upon the crop of corn. The wheat plant re- 
quu-es for its full developement a certain relative propor- 
tion of both nutritive substances, and any increase of one 
beyond this proportion makes the other not a whit more 
effective, because the additional supply exercises by itself 
no action. 

An increase of phosphoric acid alone has just as little 
influence in making the returns greater, as an increase of 
potash alone : this law apphes equally to every nutritive 
substance, potash, magnesia, and silicic acid ; no supply of 
these substances beyond the requirement of the wheat- 
plant, or its capacity of absorption, will have any effect 
upon its growth. The relative proportions of the mineral 
substances, which the plants draw from the soil, are easily 
determined by analysing the ashes of the produce. It is 
found by analysis that wheat, potatoes, oats, and clover 
receive the following proportions of phosphoric acid, 
potash, hme, magnesia, and silicic acid : — 



128 



THE SOIL. 



Wheat I'^f^ \ . 
1^ straw/ 

Potatoes (tubers) . 

Oats (Z'' \ ■ 
i^ straw/ 

Clover . 
Average 


Phosplioric acid 


Potash 


Lime and 
magnesia 


Silicic acid 




2-0 
3-2 
21 
2-6 

2-0 


0-7 
0-48 
1-03 
4-0 

1-5 


5-7 
0-4 
5-0 
1-0 

3-0 



Supposing wheat, potatoes, oats, and clover to be 
cultivated in a field for four years in succession, each of 
these plants will absorb from the soil the proportion of 
mineral constituents which it requires ; and the sum total 
divided by the number of years, viz. four, shows the 
average relative proportion of all the nutritive substances 
which the soil has lost. 

If, in the formula. 



Phosphoric acid 

<l-0 



Potass 

2-5 



Lime and magnesia 

: 1-5 



Silicic acid 

3-0) 



we determine the value of n, which is meant here to 
designate the number of kilogrammes of phosphoric acid 
which the four crops have received from the soil, we find 
for the wheat crop 26 kilogrammes of phosphoric acid, 
for the potato crop 25 kilogrammes, for the oat crop 
27 kilogrammes, and for the clover crop 36 kilogrammes 
— altogether, 114 kilogrammes; multiplying the above 
proportional numbers by this number, we obtain the sum 
total of all the nutritive substances extracted from ,the 
soil by the four crops. 

With the help of these proportional numbers, we are 
better able than before to give some more accurate 
explanations. 

Suppose that the soil of a certain field contains, in an 
available state, the requisite quantities of phosphoric acid. 



EFFECT OF INCEEASING ONE MINERAL CONSTITUENT. 129 

potash, lime, and magnesia, to supply the four crops 
stated above, but that it is deficient in the proper propor- 
tion of sihcic acid. — containing, for example, for 1 
part by weight of phosphoric acid, only 2^ parts of 
sihcic acid, in an available condition — this deficiency 
will, in the first place, be felt in the crops of cereal 
plants, whilst the potato and clover crops, on the contrary, 
will not be at all diminished. It will depend upon the 
weather to determine whether this deficiency in the 
crop of cereal plants extends both to corn and straw or 
is confined to the straw alone. A want of potash, in 
projiortion to all the other constituents, will barely affect 
the wheat and oat crops, but it will reduce the potato 
crop ; in like manner, a want of lime and magnesia will 
impair the clover crop. 

If the ground can furnish one-tenth more potash, lime, 
magnesia, and silicic acid, than corresponds to the given 
proportion of phosphoric acid — thus, if, 

Phosphoric p^ j^ Lime and gijicic acid 
acid ivi-cvsii Magnesia 

Instead of ... . 1 2-5 1-5 3-0 

The ground should be able to 

furnish .... 1 2-75 1-65 3-3 

the crops would not turn out larger than before. But if, 
in such a field, the quantity of phosphoric acid is in- 
creased, the produce will increase, until the right propor- 
tion is restored between the phosphoric acid and the 
other mineral constituents. The additional supply of 
phosphoric acid serves in this case to increase the amount 
of potash, lime, and silicic acid in the produce ; but if 
this additional supply exceeds one-tenth of the phosphoric 
acid present in the soil, the quantity in excess remains 
ineffective. Up to this Hmit, every pound — nay, every 
ounce — of phosphoric acid supplied has, in this case, a 
fully determinate action. 

K 



130 THE SOIL. 

If potash or lime alone is wanted to restore tlie right 
proportion among the nutritive substances in the soil, a 
supply of ash or lime will increase the produce of all the 
crops — the additional supply of hme effecting, in this 
case, an increase in the amount of phosphoric acid and 
potash in the augmented produce. 

If we find that a soil will not bear a remunerative 
crop of cereal plants, though it remains fruitful for other 
plants, such as potatoes, clover, or turnips, which require 
just as much phosphoric acid, potash, and lime, as the 
cereals, we may assume that the soil had the latter sub- 
stances in excess, but was deficient in silicic acid. 
And if, in the course of two or three years, during 
which other produce is cultivated on it, the land recovers 
its fertihty for cereals, this must be because it contained, 
though unequally divided and distributed, an excess of 
silicic acid also, which, during the fallow season, mi- 
grated from the places where it was in excess to those 
where it was deficient ; so that when the subsequent 
period of cultivation began, there was in all these places 
the right proportion of all the nutritive substances needed 
by cereal plants. 

For similar reasons, if peas or beans can be cultivated 
on a given field only at certain intervals, and experience 
shows that skilful, industrious tillage is usually more 
effective than manure in shortening these intervals, we 
may infer that m such cases the nutritive substances were 
not deficient in total quantity in the Avhole field, but in 
proper proportion in all parts of the field. 



131 



CHAPTEE III. 

ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 

Manures : meaning of tlie term ; their action as food of plants and means 
for impro\dng tlie soil — Effect on soils with different powers of ab- 
soi-ption — Each soil possesses a definite power of absorption ; the dis- 
tribution of the food of plants in the soil is inversely to the power of 
absorption; means of counteracting the absorptive power — Absorption 
number, notion of; comparison of in different fields; its importance in 
husbandry — Soil saturated with food of plants ; its comportment mth 
water — Quantity of food to saturate a soil — A saturated soU not re- 
quired for the growth of plants — Manuring may be compared to the 
application of earth saturated with food — Importance of the uniform 
distribution of food in manures ; fresh and rotted stall manure ; compost ; 
importance of powdered turf for the preparation of manure — Quantity 
of food in unmanured fields and their powers of production ; increase of 
the latter apparently out of proportion to the manure added ; experiments 
on this point; explanation; composition of the soil and its absorptive 
power compared with the requirements of the plants to be cultivated on 
it ; surface and subsoil plants, the tillage and manuring respectively 
required by each — Clover sickness; experiments of Gilbert and Lawes; 
their conclusions ; value of them. 

rilHE term ' manure ' is commonly used to designate all 
-^ matters wliicli, applied to a field, will increase the 
amount of its future produce, or, when the land has been 
exhausted by cultivation, will restore its capability of 
yielding remunerative harvests. 

Manuring agents act partly in a direct manner as 
elements of food, and partly, like common salt, nitrate of 
soda, or salts of ammonia, by enhancing the elTect of the 
mechanical operations of tillage, so that they frequently 
exert as favourable an influence as the actual increase of 
the nutritive substances in the ground. 

Of the two last-named compounds, nitrate of soda 



132 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 

contains a nutritive substance in the nitric acid, and salts 
of ammonia in the ammonia. Hence it is extremely diffi- 
cult in individual cases to determine whether their action 
is due to their nutritive constituents, or to the fact that 
they have brought about the absorption of other nutritive 
substances. 

In a fertile soil tillage and manuring have a definite 
relation to one another. If, after a rich harvest, the field 
is prepared by tillage alone to produce a similar rich crop 
in the next year, that is, if the mechanical means are suf- 
ficient to distribute the store of nutritive substances so 
uniformly that the plants of the foUov/ing season will find 
as much nutriment in all parts of the soil as during the 
last, any further supply of mineral constituents by manur- 
ing would be mere waste ; but, where a field is not in that 
condition, the deficiency must be supplied by manure, in 
order to restore the original power of production. Thus, 
in a certain sense, the mechanical operations of tillage 
and of manure are supplementary to one another. 

Of two similar fields, manured in exactly the same way, 
if the one has been well tilled, and the other badly tilled, 
the former will yield a richer crop, i.e. tlie manure seems 
to have a better effect upon this than upon the badly- 
tiUed field. 

If one of two farmers knows his land better, and culti- 
vates it more judiciously than the other, the former will, 
in a given time, obtain as good crops with less manure, or 
richer crops with the same quantity of manure. 

All these facts should be considered in estimating the 
value of manuring agents ; but, as science has no 
standard for measuring the results of the mechanical 
operations of tillage, this cannot be taken into account 
here, and we must confine ourselves to that which can be 
scientifically measured and compared. 



ARABLE SOILS ABSORB MINERAL MATTERS. 133 

When two fields are equally rich in nutritive substances, 
it often happens that the one, by tillage alone, or by tillage 
combined with manurmg, will be brought much sooner 
than the other into a condition to yield a succession of 
remunerative crops of cereal or other plants. 

On a light sandy soil, all kinds of manm-e act more 
rapidly and effectively than on clay. The sand is more 
grateful, say the farmers, for the manure bestowed upon 
it, and yields a more abundant return than other soil^ for 
what it has received. The nitrogenous manures, such as 
wool, horn-shavings, bristles, and blood, which, as we 
know for a certainty, act by the formation of ammonia, 
frequently exercise a far more favom-able influence upon 
many plants than ammonia itself. In other cases, bone- 
earth acts more powerfully upon the future crop than 
superphosphate of lime ; and sometimes ash will prove 
more fertilising than if the amount of potash contained in 
it were directly laid upon the field. 

All these facts are most intimately connected with the 
faculty of arable soils to extract or absorb phosphoric acid, 
ammonia, potash, and silicic acid from their solutions. 
The restoration of the productive power to an exhausted 
field by the mechanical operations of tillage and fallowing 
alone, without manure, presupposes that in certain parts 
of the field there must have been an excess of nutritive 
substances which dispersed in the soil and extended to 
other places where such substances were deficient. 

This distribution demands a certain time. The excess 
of nutritive elements must first be dissolved, that they 
may be able to move towards those parts which have lost 
their elements of food by a previous harvest. The closer 
these superabundant deposits he to each other, the shorter 
is the way over which the substances have to travel ; and 
the less the absorptive power of the intervening earth 



Cubic 


Cubic 


decimetre 


inclies 


1 = 


61 ( 




J5 




J? 




J> 




)? 



134 ACTION OF SOIL ON FOOD OF PLANTS IN MANUEE. 

particles for these nutritive substances, the more speedily 
wiU the productive power of the soil be restored. 

Every arable soil possesses, for potash and the other 
substances mentioned, a determinate power of absorption, 
which may be expressed by the number of milhgrammes 
absorbed by 1 cubic decimetre (=1000 cubic centi- 
metres) of earth. Thus, for instance : — 

Milligrammes Grains 

61 of lime soil from Cuba, absorbed 1360 = 21 potash 

loam ,, Bogenhaiisen ,, 2260 = 35 „ 

soil ,, Weilienstephan 2601 = 40 ,, 

soil „ Himgary „ 3377 = 52 „ 

garden mould Mimicli ,, 2344 = 36 ,, 

It will be seen at once that these differences in absorp- 
tive power are very considerable. One volume of earth 
from Weilienstephan absorbs nearly twice as much potash 
as an equal bulk of soil from Cuba ; the Hungarian earth, 
here examined, absorbs 2^ times as much. 

These figures show that a certain quantity of potash, 
say 2600 milligrammes, if supphed to the Weihenstephan 
soil, will spread in a space of 1 cubic decimetre of earth. 
If we were to pour the potash, in solution, on a small 
plot of ground, 1 square decimetre in area, the potash 
would penetrate to a depth of 1 decimetre ( = 3'94 inches), 
and no deeper ; every cubic centimetre (="061 cubic 
inch) would receive 2-6 milligrammes (==-04 grain) of 
potash, but the layers beneath would receive none, or at 
least no appreciable quantity of it. 

If the same solution were poured on an equal area of 
Hungarian or Cuban soil, the potash filtering through 
would penetrate, in the former, to a depth of somewhat 
above 7 centimetres (==2-7 inclies); in the latter, to a 
depth of 19 centimetres (=7 '5 inches). 

The diffusibility of potash in a soil is in an inverse 



ABSOEPTIYE POWEE OF SOIL FOR SILICIC ACID. 135 

ratio to the absorptive power of that soil; half the 
absorptive power corresponds to double the difFusibihty. 
In a similar way potash will spread in a field during the 
time of fallow. Erom the spot where the potash is set 
free from a silicate by disintegration, it will diffuse itself 
through a volume of earth so much the larger in propor- 
tion as the absorptive power of the earth for potash is 
smaller. 

The absorptive power of arable soil for silicic acid 
differs just as much as for potash. 

Thus from a solution of silicate of potash, 1 cubic 
decimetre (=61 cubic inches) of these different soils ab- 
sorbed the following quantities of silicic acid: — 



Forest soil 


Hungarian 


Garden mould I. 


Bogenhausen 


Garden mould II, 


ililligr. Grains 


Milligr. Grains 


Milligr. Grains 


Milligr. Grains 


Milligr. Grains 


15=0-23 


2644=43-8 


2425=37-3 


2007=31 


1085=16-7 



Wlience to express the relative diffusibihty of sihcic 
acid in these soils, we have the following proportion : — 

Hungarian Garden mould I. Bogenhausen Garden mould II. Forest soil 

1-0 1-09 1-31 2-43 17-6 

The same quantity of silicic acid which would saturate 
1000 cubic centimetres of Hungarian earth, would 
furnish a maximum supply for 1311 cubic centimetres of 
Bogenhausen loam, 2430 cubic centimetres of garden- 
mould II., and 17,600 cubic centimetres of forest soil. 

Ammonia, in the pure state, or in the form of salts of 
ammonia, is absorbed by arable soil just in the same way 
as potash : one kilogramme (=2-2 lbs.) of the following 
earths Avill absorb respectively these quantities of am- 
monia : — 



Cuban 


ScUeissheim 


Garden mould 


Bogenhausen 


Milligr. Grains 


Milligr. Grains 


Milligr. Grains 


Milligr. Grains 


5520 = 85 


3900=60 


3240=49-9 


2600=40 



136 ACTION OF SOIL ON FOOD OF PLANTS IN MANTJEE. 

which gives the following numbers for the relative diffu- 
sibility of ammonia : — 

Cuban SoUeissheim Garden mould Bogenhausen 

1-0 1-24 1-50 2-12 

The absorptive power of arable soils for phosphate of 
lime, phosphate of magnesia, and phosphate of magnesia 
and ammonia, may be determined in the same way, and 
the relative diffusibility of these several constituents in 
different soils may be expressed numerically. 

By the term ' absorption number,' we designate, in the 
following pages, the quantity reckoned in miUigrammes 
(= 0-0154 grain) of the several mineral constituents, 
which one cubic decimetre ( = 61 cubic inches) of earth 
extracts from their solutions. 

To determine the condition of a field, the action of the 
manures applied to it, and the depth to which the several 
nutritive substances will penetrate, it is important to 
establish proportionately the absorptive power of the soil 
for each of them ; thus, for example, 1 cubic decimetre 
of Bogenhausen loam absorbs : — 



Relative diffiisibility 


Ammonia 


Phosphate of 

Magnesia and 

Ammonia 


Potash 


Phosphate 

of 

Lime 


Milligrammes 
2600 
I'O 


Milligrammes 
2565 

roi 


Milligrammes 
2366 
1-10 


Milligrammes 
1098 
2-36 



Accordingly, the second series of these numbers ex- 
presses that if a certain quantity of ammonia in its passage 
through the soil penetrates to a depth of 10 centimetres, 
the same quantity of potash wiR attain a depth of 11 
centimetres, and a Hke quantity of phosphate of hme wiU 
reach 2 3 "6 centimetres. 

In a soil hke the Bogenhausen, which absorbs per cubic 
decimetre 1098 milhgrammes of dissolved phosphate of 
lime, let us suppose that granules of phosphate of hme 



DISPEESION OP PHOSPHATE OP LIME IN SOIL. 137 

are dispersed, and tliat in one spot of the ground one of 
these granules weighing 22 minigrammes (^ of a grain) 
during the course of a certain time becomes soluble in 
carbonic acid water, and spreads in the surrounding soil ; 
first of all the earth immediately around this granule will 
be saturated with phosphate of lime, then as the carbonic 
acid remains in the water and its solvent power con- 
tinues, a fresh solution will be formed, which will again 
offer phosphate of Hme for absorption to a wider extent 
of earth ; at length, when the 22 milligrammes of phos- 
phate of lime are thoroughly diffused in the surrounding 
earth, they will supply 20 cubic decimetres of earth with 
the maximum of this nutritive substance in the form best 
suited for absorption. The rapidity with which the phos- 
phate of Hme will dissolve and spread depends upon its 
extent of surface ; accordingly, if we suppose the granule 
to be converted into a fine powder, a solution will be 
formed richer in phosphate of hme just in proportion to 
the greater number of particles exposed within the same 
time to the solvent action of the carbonic acid. There- 
fore, assuming that in a certain state of greater division 
twice or three times as much is dissolved in a given time, 
we infer that distribution under favourable circumstances 
will take place in one-half or one-third of the time it 
would take without the division. 

If, therefore, in a given case the restoration of the 
productive power in a soil by fallowing or manuring 
depends upon the earth when drained of phosphoric acid 
by the roots of plants receiving the needful phosphoric 
acid back again from the surrounding earthy particles, 
it follows that with an equal amount of earthy phos- 
phates the time required to accomplish this end will be 
shortened in proportion to the division of the earthy 
phosphates. 



138 ACTION" OF SOIL ON FOOD OF PLANTS IN MANUEE. 

Straw manure, after decay, leaves silicate of potash 
behind, and in the process of putrefaction evolves carbonic 
acid, which by its action upon the silicates sets free silicic 
acid ; hence by using this manure the diffusion of silicic 
acid must be promoted as the organic matters absorb 
none of it, and they, when mixed with the earth, must 
diminish the absorptive powers of the soil. 

The forest soil above mentioned absorbed only very 
small quantities of silicic acid from its alkaline solutions ; 
and it is evident that the addition of such soil to the 
Hungarian earth would have the effect of diffusing through 
a larger volume of earth the silicic acid set free by 
disintegration. 

It is not, however, the case with every soil, that its 
absorptive power for silicic acid decreases in equal pro- 
portion to the quantity of combustible substances which 
it contains. Thus the Hungarian earth above alluded to 
contains more (9-8 per cent.) combustible matter than the 
Bogenhausen loam (8-7 per cent.), yet its absorptive power 
for siHcic acid is not less but greater than that of the 
latter. Hence it follows that there are other circum- 
stances which influence the absorptive power of the soil 
and consequently the cliffusibility of silicic acid. A soil 
abounding in hydrated silicic acid will, under any circum- 
stances, absorb less sihcic acid than one deficient in that 
acid, even though the latter soil should contain a much 
larger amount of or2;anic substances. 

The ' absorption numbers ' of two different arable soils 
afford no criterion for determining the quality of the soil 
or the amount of nutritive substances which it contains ; 
they merely tell us that, in the one soil, the elements of the 
food of plants will spread beyond certain places, further 
than in the other ; that the one soil opposes greater ob- 
stacles to their diffusion than the other. The farmer, in 



FOOD OF PLANTS IN SANDY SOILS AND LOAMS. 139 

learning the strength of these obstacles, finds out by 
experience whether they exert a beneficial or adverse in- 
fluence upon the cultivation of his fields, and ascertains 
the means of removing the injurious or strengthening 
the beneficial influences. 

On comparing a fruitful sandy soil with an equally 
fruitful loam or marl, as regards the nutritive substances 
contained in them, we are surprised to find that the sand 
with one-half, or even one-fourth, of the total substances 
contained in the loam, will furnish an equally rich 
harvest. To understand this circumstance properly, we 
must remember that the nutrition of a plant depends less 
upon the quantity, than upon the form of the nutri- 
ment in the soil ; just in the same way as,, for example, 
half an ounce of animal charcoal presents as large an acting 
surface as a pound of wood charcoal. If the smaller 
quantity of nutritive substances in the sandy soil presents 
as large a surface for absorption as the larger quantity of 
those substances in the loam, the plants must thrive as 
well upon the former as upon the latter. 

If a cubic decimetre of a fruitful loam is mixed with 9 
cubic decimetres of silicious sand, so that every particle 
of sand is surrounded with particles of loam, as many 
root-fibres and particles of loam wiU come into contact in 
the mixed as in an equal volume of the unmixed soil ; 
and if all the particles of loam can yield the same nutri- 
ment, plants will receive from the mixed just as much as 
from the unmixed soil, though, on the whole, the latter is 
ten times richer. 

All fruitful sandy soils consist of a mixture of sand with 
more or less clay or loam ; and as siHcious sand has a very 
limited power of absorbing potash and the other mineral 
constituents of plants, the ingredients of the supplied 
manure, which have become soluble, spread sooner and 



140 ACTION OP SOIL OX FOOD OF PLANTS IN MANURE. 

penetrate deeper into a sandy soil, whicli also gives back 
comparatively more of them than any other soil. In 
many cases therefore a stiff loam may be improved by 
sand ; as, on the other hand, the addition of loam to a 
sandy soil v^ill cause the nutritive substances, supplied by 
the manure, to remain nearer the surface, or to be re- 
tained more firmly in the arable top layer. 

But as a sandy soil gives up at harvest more nutritive 
substances in proportion to what it contains, than a fruit- 
ful loam, a more speedy exhaustion is the consequence ; 
its povi^er of production does not last long, and can only 
be sustained by frequent manuring, to supply the con- 
stituents which have been removed. Exactly in the same 
degree, as the manure acts more beneficially in restoring 
the productive power, the effect of the mechanical opera- 
tions of tillage becomes less marked. 

The same causes which restore to an exhausted loam 
a large portion of its lost productive power, if the land is 
but sufficiently broken up by the plough, are at work in 
a sandy soil also ; but they produce little or no result, 
because the sand is deficient in those substances which 
the" action of the plough is intended to render available. 

As the surface of a hectare (2| acres) represents 1 mil- 
lion square decimetres, the absorption numbers express the 
number of kilogrammes of potash, phosphoric acid, and 
silicic acid, which, when applied on a field, will spread 
from the surface downwards to a depth of 10 centimetres 
(about 4 inches). Volker, Henneberg, and Stohmann, 
in experiments made upon different soils to determine 
their absorption numbers for ammonia, observed that the 
earth retained a greater quantity from a concentrated than 
from a dilute solution of ammonia or salts of ammonia ; 
whence it follows, as a matter of course, that the am- 
monia is divided between the water and the soil, and that 



ABSORPTION OF AMMONIA BY SOIL. 1^1 

from a soil fully saturated with ammonia, pure water will 
extract a certain quantity of it ; just as charcoal wiU com- 
pletely withdraw the colouring matter from a slightly 
coloured fluid, but from one more deeply coloured will ex- 
tract a much larger quantity ; a part of which, however, 
is but feebly combined and may be removed by water. 

In Volker's experiments, treatment with a copious 
amount of water extracted one-half the ammonia from a 
soil saturated therewith ; the other half was retained by 
the earth. 

Soils which contain much decaying vegetable matter 
absorb more ammonia and retain it more firmly than soils 
that are poorer in decaying organic substances. Even 
assuming that two cubic decimetres of earth, instead of 
one, are required to retain completely the amount of 
ammonia indicated by the absorption number, it is clear 
that ordinary manuring with an agent abounding in am- 
monia, such as guano or salts of ammonia, can enrich the 
earth with this substance only to a very inconsiderable 
depth. 

To saturate, with ammonia, a hectare (2 J acres) of 
Bogenhausen loam, from the surface downwards to the 
depth of one decimetre, fully, or to half-saturate it to the 
depth of two decimetres (7*8 inches), would require a 
supply of 2600 kilogrammes or 52 cwts. of pure ammonia, 
or 200 cwts. of sulphate of ammonia. 

If 800 kilogrammes of guano, containing 10 per cent, 
of ammonia, are applied to a hectare of Bogenhausen soil, 
the amount of ammonia added is 80 kilogrammes (=176 
lbs.), which is a little more than the thirtieth part of the 
quantity required to half-saturate the soil to a depth of 
20 centimetres. Without the plough and harrow, the quan- 
tity of ammonia contained in the guano would not pene- 
trate, at the furthest, deeper than 7 milHmetres ( = 0-27inch). 



142 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 

But to thrive well, plants do not require a soil saturated 
with nutritive substances; for, the absorption numbers 
we have quoted sufficiently show how far the arable 
soils are from a state of complete saturation. All that 
plants need for their proper nutrition is that their roots, 
downwards in the soil, should come in contact with a 
certain quantity of saturated earth ; and the mechanical 
operations of tillage have the important object of con- 
veying earthy particles saturated with nutritive substance 
and of mixing them with others, which by preceding culti- 
vation have become poorer in those constituents. 

The average crop from a hectare of wheat (2000 kilo- 
grammes=4400 lbs. of grain, and 5000 kilogrammes= 
11,000 lbs. of straw) contains 52 million milligrammes 
( = 114-4 lbs.) of potash, 26 million milhgrammes ( = 57'2 
lbs.) of phosphoric acid, and 54 million milligrammes 
(=118-8 lbs.) of nitrogen. Assuming the nitrogen to be 
supplied by the soil, the wheat plants growing on a square 
metre (==10 -7 5 square feet) receive the ten-thousandth part 
of the potash, phosphoric acid, and nitrogen, or altogether 
13,200 milligrammes (=203-3 grains). Supposing 100 
plants to grow upon a square metre, each of these takes 
up from the soil 132 milligrammes of these constituents, 
or 54 milligrammes of nitrogen=65 milligrammes or 1 
grain of ammonia, 52 milligrammes (=0*8 grain) of pot- 
ash, and 26 milhgrammes (^0*4 grain) of phosphoric acid. 

Each cubic centimetre (=:-06 cubic inch) of Bogen- 
hausen loam absorbs to saturation 2-6 milligrammes 
(='04 grain) of ammonia, 2*3 milligrammes ( = 0-35 grain) 
of potash, and 0-5 milligrammes (^-008 grain) of phos- 
phoric acid ; therefore, to restore a sufficiency of these 
constituents which the wheat plant has taken from the 
soil, would require a supply of 25 cubic centimetres of 
the saturated earth, and 25 milligrammes of phosphate of 



EAETH SATUEATED WITH MINEEAL MATTEE. 143 

lime for eacli square decimetre of the field. Calculated 
upon a square decimetre (=15^ square inches) of surface 
and a depth of 20 centimetres (=7*8 inches), these 25 
cubic centimetres constitute the eightieth part of the 
entire mass of earth. 

The experiments of Naegeli and Zoeller, before des- 
cribed, furnish a good example of this kind of manuring. 
The manure consisted of turf, partly satm^ated with nutri- 
tive substances and mixed with three volumes of turf almost 
absolutely unfruitful ; this constituted a soil of the same 
degree of fertility as good garden mould. 

Such an addition of earth saturated with mineral con- 
stituents does not usually take place ; but the ordinary 
method of manuring comes exactly to the same result. 
The field is dressed with liquid or sohd manuring matters 
containing nutritive substances, which combine imme- 
diately if in solution, gradually if requiring a certain time 
for solution, with the earthy particles with which they 
are in contact, and saturate them ; and it is properly 
this earthy saturated with manuring matters on its outer- 
m,ost surf ace or in the inner parts with which the farmer 
manures^ i.e. with which he replaces the mineral con- 
stituents withdrawn from the soil. 

Experience has taught the agriculturist which parts of 
the soil may be enriched with nutritive substances most 
profitably for himself, or rather for his plants ; and it is 
remarkable in the highest degree how he has found out 
the proper method of manuring in accordance with the 
nature of the intended crop, the soil, and the period m 
which the plants are developed ; also whether to proceed 
by simple top-dressing or by ploughing the manure in to a 
greater or less depth,* 

* * Joiirn. of the Royal Agric. Soc. England,' t. 21, p. 330. 



144 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 

In these respects tlie successes of the agriculturist 
would be still greater if the nutritive substances con- 
tained in the manure principally used, namely, farm-yard 
manure, were more uniformly mixed and distributed, 
because this would lead to a more uniform distribution 
of them in the soil. 

Farm-yard manure is a very irregular mixture of 
decaying straw and vegetable remains, combined Avith 
soHd animal excrements, the latter constituting the 
smaller portion of the whole mass : it is soaked with 
fluids which hold ammonia and potash in solution. If a 
hundred samples be taken from a hundred different parts 
of a dung-heap, the analysis of each sample will show 
different proportions of nutritive constituents : hence it is 
evident that by a dressing with farm-yard manure hardly 
two spots in the soil will receive the same amount of 
nutritive substances. 

The spot occupied by a dung-heap on a field during 
rainy weather, will be marked in the whole period of 
vegetation, and often even in the second year by a more 
luxuriant growth of plants, especially of cereals, though 
the plants growing on it will not always furnish a per- 
ceptibly greater yield of grain. If the potash and 
ammonia received by this spot above what was required for 
the formation of grain, had been more evenly distributed, 
and thus accessible to the plants in other places, the yield 
of corn from those plants would have been increased ; 
whereas the excessive accumulation in one place merely 
increased the yield of straw. The unequal distribution 
of the other ingredients of farm-yard manure in the soil 
leads to a similar inequality in the developement of 
the several parts of the cereal plants. On an ideal 
field, with the nutritive substances supposed to be distri- 
buted with perfect uniformity, and all accessible to the 



USE OF EARTH SATURATED WITH MANURE. 145 

roots, all the cereal plants, other conditions being the 
same, should attain the same height, and each ear yield 
the same nmiiber and weight of grains. 

In the short, rotten farm-yard manure, the nutritive sub- 
stances are much more uniformly distributed than in the 
fresh straw manure ; and the agriculturist effects a still 
more uniform diffusion by mixing the dung with earth, 
and turning it into so-called compost. As dung and all 
other manuring agents act only through the medium of the 
earthy particles that have become saturated with the nutri- 
tive substances contained in the manure^ it is, under certain 
circumstances, advantageous for the farmer to prepare a 
saturated earth, by help of his farm-yard manure, and to 
use this composition, which may of course be made on 
the field itself. If, in accordance with Voelker's valuable 
experiments, we assume one cubic metre {- 
feet) of farm-yard manure (500 kilogrammes or 
pounds) to contain 660 pounds of water, 6 pounds of 
potash, and 12 pounds of ammonia ; and if this were 
mixed with 1 cubic metre of earth, of which 1 cubic 
decimetre (= 61 cubic inches) absorbs 3000 milli- 
grammes (=46*2 grs.) of potash, and 6000 milligrammes 
( = 92-4 grs.) of ammonia ; then, after the complete decay 
of organic matter in the manure (about 25 per cent, of 
its weight), and the evaporation of one-half of the water, 
the result would be 1| cubic metre of earth fuUy saturated 
with all the nutritive substances in the manure. Soils 
that will absorb the stated amount of potash and 
ammonia are everywhere to be found, and the farmer 
will have no difficulty in choosing the earth most suitable 
for his compost heaps. 

It is well known that dung exercises a mechanical 
action also, tending to diminish the cohesion of a compact 
soil, or to make a heavy soil lighter and more porous. 

L 



146 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 

For soils of this kind composts are not so well suited; 
and, instead of the earth, some very loose body ought to 
be substituted for mixing with the manure. Turf-dust 
will be found to answer the purpose best.* 

If the crops obtained from many fields by manuring 
with farm-yard manure, bone-earth, guano, and in many 
cases also with wood-ashes and lime, are compared with 
what the same fields will yield in the unmanured state, 
the effect of these manures seems truly marvellous. 

The yield of an unmanured field must correspond Avitli 
the available nutritive substances which it contains ; a 
lower crop corresponds to a smaller store of these matters. 
In any one of the cases stated, if we compare the amount 
of nutritive substances in the unmanured portion of a 
field with the crop which it produces, and then compare 
the additional nutritive substances or the quantity of dung 
with the increased crop, the increase appears to be beyond 
aU proportion much greater than the additional supply. 
Hence we are led to suppose that the phosphoric acid, 
potash, and ammonia given in the manure must be much 
more efficacious than the substances present in the soil, or 

* It is, perhaps, much more important than manuring with composts, 
which always involves much labour and more carriage, to take ad- 
vantage of the absorbent properties of earth and turf, for fixing the 
nutritive substances contained in liquid manure. By covering the 
ground of a dunghill, on an area of 10 metres square (=:10*5 sq. feet) 
with a layer of loose turf, 1 metre (=3'3 feet) deej), a bed of 100 
cubic metres (=3,500 ciibic feet) of turf is formed, into which the 
liquid portion of the manure in the dunghill may safely be allowed to 
soak without the least risk of losing the smallest portion of its useful 
ingredients. The turf may then be used, like dung, for maniu-ing, and 
of coiu'se must be renewed every year. On fields Avhich are not tilled, 
such as meadows, liquid manure Avill naturally act with greater raj)idity. 
The turf found in the neighbourhood of Munich, Avhen reduced to pow- 
der, absorbs 7"892 grammes (= 122 grains) of potash, and 4-169 grammes 
(zz:64 grains) of oxide of ammonium, per 1000 cubic centimetres ( = 01 
cubic inches) weighing 330 grammes (11-|- ozs.). 



BAVARIAN EXPERIMENTS. 



147 



that the greater portion of them m the soil was ineffective, 
and that its power of production had depended chiefly 
upon the supply of manure. Thus it arises, that while 
some farmers beheve that all manure can be dispensed 
with because tillage alone is enough to render a field pro- 
ductive, others suppose that the field can be kept fruitful 
only by manuring. All these views are based upon indi- 
vidual cases and have no general application ; for neither 
one nor the other of the contending parties have any clear 
knovfledge of the true causes upon which the power of 
production of this kind is founded. 

In the experiments made in the year 1857, by order 
of the General Committee of the Eavarian Agricultural 
Union, on the action of phosphorite upon certain fields at 
Schleissheim deficient in phosphoric acid, the following 
crops of summer wheat were reaped from two plots of 
ground, one unman ured the other dressed, per hectare 
(= 2^ acres), with 241-4 kilogrammes (= 5301bs.) of phos- 
phoric acid, 657*4 kilogrammes (=13 cwt.) of phosphorite 
decomposed by sulphuric acid : — 



Manured with 657 kilogrms. 

of phosphate of lime 
Unmaniired 


1857 1 


'total crop 


Corn 


Straw 


Cwt. 
Kilogr 

5114-7 = 105-0 
2301-0= 45-0 


Kilogr. Cwt. 

1301-7 = 25-5 
644-3 = 12-5 


Kilogr. Cwt. 

3813-0 = 75-0 
1656-7 = 32-5 



From a chemical analysis made by Dr Zoeller, of the 
Munich Laboratory, the soil of this field was found to 
give up to cold hydrochloric acid a quantity of phosphoric 
acid, which, calculated per hectare to a depth of 25 
centimetres, amounted to 2376 kilogrammes = 5170 
kilogrammes of phosphate of lime. 

L 2 



148 ACTION OP SOIL ON FOOD OF PLANTS IN MANURE. 

Tlie quantity of phosplioric acid in the corn and straw 
of the crop reaped amounted altogether to : — 

Mlogr. lbs. 

From the manured plot . . 17*5 = 38'0 of phosphoric acid 
From the unmaniired plot . 8-0 = 17 "6 „ 

Surplus obtained by manuring . 9-5=20-9 „ 

In the 657*4 kilogrammes of phosphorite the field 
received altogether 241 "4 kilogrammes of phosphoric 
acid ; accordingly, the surplus amounted only to gV^h of 
the phosphoric acid supplied in the manure. 

There is nothing surprising in this result, as the addi- 
tional phosphoric acid was not given to the plants but to 
the whole field. Had it been possible to surround each 
root with so much phosphoric acid or phosphate of hme 
as the surplus crop of corn and straw required for its 
formation, 9^ kilogrammes of phosphoric acid would have 
sufficed to double the produce of the unmanured plot ; 
but in the way in which the manure was actually applied, 
every part of the field received an equal share of 
j^hosphoric acid. 

Thus, of the total amount of 241 '4 kilogrammes, only 
9'5 kilogrammes came into contact with the roots of the 
plants, the remainder, though quite suitable for food, 
remaining inactive. To enable the plant to take up one 
part of phosphoric acid, it was necessary to supply the 
field with five-and-twenty times this quantity. 

On the other hand, the effect of the manure appears out 
of all proportion greater as compared with the store of 
phosplioric acid in the field. 

The quantity of phosphoric acid contained in the corn 
and straw reaped from the unmanured plot is 5 Joth of 
the total amount of phosphoric acid in the field ; that in " 
the surplus crop is gV^^^ ^^ ^^^® phosphoric acid supplied 
by the manure. As the manured plot gave double the 



RATIO OF CROP TO PHOSPHORIC ACID IN SOIL. 149 

produce of the unmanured, the effect of the phosphoric 
acid supphed by the manure is apparently twelve times 
greater than that of the acid originally contained in the 
soil. 

The quantity of phosphoric acid supplied (241-4 kilo- 
grammes) amounted to -njth of the total quantity in the 
field (2376 Idlogrammes). If the action of both had 
been alike, the surplus crop should have corresponded to 
the additional supply, but instead of being y^th greater, 
it was double the crop obtained from the immanured plot. 

This fact is explained by the absorptive number of the 
Schleissheim soil for phosphoric acid or phosphate of 
lime. 

If the store of phosphoric acid in the field had been 
uniformly distributed in the form of phosphate of lime 
(5170 kilogrammes) to a depth of 25 centimetres (9*8 
inches), each cubic decimetre (61 cubic inches) would 
contain 2070 milligrammes (32 grains), each cubic centi- 
metre about 2 milligrammes of phosphate of hme. 

The field was manured with 6 57 "4 kilogrammes of 
phosphorite in a soluble state, corresponding to 525 
million milligrammes (525 kilogrammes) of pure phosphate 
of lime. 

As determined by direct experiments, 1 cubic deci- 
metre of Schleissheim soil absorbs 976 milligrammes of 
phosphate of Hme. Each square decimetre received in 
the manure 525 milligrammes, which, dissolved by rain 
water in its descent through the soil, would be sufficient 
to saturate the earth fully, Avith phosphate of lime, to a 
depth of 5-4 centimetres (rather more than 2 inches), or to 
half-saturate it to a depth of 10-8 centimetres. Hence the 
manuring served to enrich the upper layer of the soil with 
phosphate of lime, not to the extent of jQ-th, but to 50 per 
cent., and the greater part of this in a state available for 



150 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 

the nutrition of plants. The absorptive power of the soil 
explains, therefore, why the crops obtained from manured 
fields are rather in proportion to the nutritive substances 
supphed in the manure, than to the store of these elements 
originally present in the soil. 

The operation of manuring agents, severally or jointly 
applied, is even more marked upon soils which are poorer 
in nutritive substances than the field at Schleissheim above 
mentioned. 

The following results were obtained on a field broken 
up for the purpose, which had not been touched by the 
plough for fifteen years, and had served as pasture for 
sheep. The entire surface -layer of the ground at 
Schleissheim is 6 inches deep at most ; below this there is 
no more soil, but a bed of rubble stones, which might be 
compared to a sieve with meshes an inch wide, through 
which the water runs freely ; the crop obtained from the 
unmanured portion wiR give some idea of its sterility. 
Another portion was manured with superphosphate of 
lime ; the quantity used per hectare (=2^ acres) was 525 
kilogrammes ( = 10 cwt.) of phosphorite decomposed by 
sulphuric acid, containing 193 kilogrammes of phosphoric 
acid, or 420 kilogrammes (=8 cwt.) of phosphate of hme. 

Crop of winter-rye in 1858 at Schleissheim, per hec- 
tare : — 



\ 


Total crop 


Corn 


Straw 


Kilo. Cwt. 


Kilo. Cwt. 


Kilo. C\vt. 


Maniired with phosphorite 








(rendered soluble by sul- 








phuric acid) =525-3 kilo. 








(10 cwt.) containing 192-8 ) 


1995-4=391-0 


654-2 = 128-0 


1341-2 = 200-0 


kilo. (3-8 cwt) P O5, cor-/ 








responding to 420 kilo. 








(8 cwt.) of pure phosphate 








of lime. 








Unmanured . 


397-6= 7-8 


115-0= 2-3 


282-6= 5-5 



THE SURFACE SOIL AND MINEEAL MATTERS. 151 

Dr. Zoeller found by analysis that this field contained, 
per hectare, to a depth of 6 inches, only 727 kilogrammes 
(^14 cwt.) of phosphoric acid. 

The plot manured with phosphoric acid produced six 
times more corn and five times more straw than the un- 
manured plot. It will be observed that, however strik- 
ingly the action of manure was exhibited, this more 
abundant crop did not equal that in the experiment pre- 
viously mentioned of the unmanured plot kept for a con- 
siderable time under culture. Upon comparing the 
amount of phosphoric acid contained in the two fields, 
we find that as the sheep pasture, to the depth of 6 inches, 
contained only half as much as the other (tiUed but 
unmanured), the dressing with superphosphate was only 
just sufiicient to make the sheep-meadow, to the depth of 
8 or 10 centimetres ( = 3 to 4 inches), equal to the other 
unmanured plot, in respect of the phosphoric acid con- 
tained in it. 

These considerations explain how it is that by the 
absorption of nutritive substances in the upper layers of 
the soil a supply of these constituents or manuring ingre- 
dients, small in comparison to the total store in the 
ground, exercises so remarkable an action in the increase 
of produce, in the case of plants which draw their food 
chiefly from the upper layers of the arable surface soil. 

If the action of the mineral constituents depends upon 
the sum of effective particles in certain places in the soil, 
the action rises with the number of particles by which 
the sum has been increased in these very places. 

A more accurate acquaintance with the composition of 
arable surface soil, and its relation to the nutritive sub- 
stances, together with a consideration of the nature and 
requirements of plants, must gradually lead to a compre- 
hension of many other phenomena in agriculture, which 



152 ACTION OF SOIL ON FOOD OF PLANTS IN MANUEL'. 

hitherto are quite unexplained, and to many farmers are 
absolute mysteries. Although we know most accurately 
the general laws of the growth of plants, as far as these 
stand in connection with soil, air, and water, yet in many 
cases it is extremely difficult to discover the causes that 
render a soil unproductive for one culture -plant, e.g. peas, 
while the same soil is fruitful for other plants which 
require the same nutritive substances as peas, and often 
in still greater quantity. If the ground is rich enough 
in nutritive substances for these other plants, why is it 
that they do not act in the same way upon the peas ? 
What causes prevent the latter from appropriating the 
nutritive substances, which the ground offers to other 
plants in a perfectly available condition ? FinaUy, how 
comes it that this very soil, after a few years, will again 
yield a remunerative crop of peas, although by inter- 
vening harvests we have rather impoverished than en- 
riched its store of nutritive substances ; and that peas, 
when sown among oats, barley, or summer corn, will 
often yield a higher crop than when they grow alone 
upon a field, and have not to share Avith other plants the 
store of mineral constituents ? 

Analogous facts are observed in the cultivation of 
clover. In many districts, a field, after producing many 
clover crops, will become almost unfruitful for that plant. 

In such cases, manuring fails in restoring to the field 
the power of producing clover ; but after several years, 
during which the same field continues to give remune- 
rative crops of cereal and tuberous plants, the soil again 
becomes for a while fruitful for clover. 

For a considerable number of our cultivated plants we 
have a pretty accurate knowledge of specific manuring 
agents, i.e. those which have a pecuharly ftivourable 
influence upon the majority of fields. Farm-yard manure, 



DIFFICULTIES NOT ALWAYS EXPLAINED. 153 

as a rule, acts beneficially in all cases ; salts of ammonia 
are especially valuable for cereals, superphosphate of lime 
for turnips ; bone earth and ashes will perceptibly in- 
crease the produce of fruitful clover-fields, and, in like 
manner, a supply of Hme will often make a field fruitful 
for clover, though otherwise unable to bear it. 

But upon fields which have become, as it is termed, peas 
or clover sick, that is, have lost their power of producing 
these plants, all these matters otherwise favourable for 
their growth exercise beyond a certain time no further 
beneficial action. It is this fact in particular which 
embarrasses the practical farmer, and makes him doubt 
the lessons taught by science. 

Wlien the farmer is compelled to give up for many 
years the cultivation of plants which he had found remu- 
nerative, and science has no power to help him over his 
difficulties, what is the use of theory ? So says the agri- 
culturist who is himself unacquainted with the essence of 
theory. 

It is a common error to fancy that an accurate know- 
ledge of theory will give the power of explaining all 
cases that occur. Theory of itself does not explain a 
single phenomenon in astronomy, mechanics, physics, or 
chemistry ; it studies and points out the causes which lie 
at the foundation of all phenomena, not the special causes 
upon which an individual phenomenon depends. 

Theory requires that the causes which govern each 
individual case should be sought out one by one, and then 
the explanation is the proof or exposition of the manner 
in which they work together to produce the particular 
fact. It teaches us what to look for, and how to employ 
proper experiments in the discovery. 

The reason why we have arrived at no conclusions 
about the facts just mentioned, depends chiefly upon this, 



154 ACTION OF SOIL ON FOOD OF PLANTS IN MANUEE. 

tliat liitlierto tlie practical farmer has troubled himself 
very little about the causes of those facts, as, indeed, the 
investigation of causes is not his proper business ; while 
those who have undertaken this task show, by the way in 
which they attempt to discharge it, that they are but little 
acquainted with the plant as an organised being, having 
pecuhar requirements which must be accurately known 
by all who would cultivate it properly. 

In the following remarks I shall compare a pea-plant 
with a cereal, and shall call the attention of agricultur- 
ists to certain peculiarities which have to be considered 
in the cultivation of both plants. 

A moderately moist, strong soil, not too cohesive and 
perfectly free from weeds, is particularly suited for peas 
and barley ; a well-tilled, calcareous loam or marl is the 
best for both plants. An arable surface soil 6 inches 
deep suffices for barley, which, with its fme-matted roots 
spreading in tufts, finds a loose subsoil rather injurious 
than beneficial. Presh manuring just before sowing acts 
powerfully on the growth of barley. Whilst the barley- 
corn should not lie lower than 1 inch, the pea thrives 
best if the seed is put 2 or 3 inches deep in the soil. The 
roots of the pea-plant do not spread sideways but go 
deep into the earth ; hence peas require a deep soil tilled 
down to the lower layers, and a loose subsoil. Fresh 
manure has scarcely any influence upon the growth of 
peas. 

It results from these pecuKarities of both plants, that 
the barley derives the conditions of its growth principally 
from the arable surface soil, the pea principally from 
the deeper layers of the soil. What the ground may 
contain below the depth of 6 inches is a matter of indif- 
ference for the barley ; the contents of these deeper 
layers are everything to the pea. 



GEOAVTH OF PEA AND BARLEY COMPAEED. 155 

If we now inquire what demands are made upon the 
soil by the two plants, we find from Mayer's investiga- 
tions (' Eesuhs of Agricultural and Chemical Experiments, 
Munich, 1857,' p. 35), that the pea-seeds contain one-third 
more ash constituents (3-5 per cent.) than the barley- 
corns, and that the amount of phosphoric acid is pretty 
much the same in both (2-7 per cent.). Therefore, all 
other conditions being equal, the subsoil from which the 
pea derives its phosphoric acid must be as rich in that 
ingredient as the arable surface soil which supphes it to 
the barley. 

The case is different with nitrogen — for the same 
amount of phosphoric acid, peas contain nearly twice as 
much nitrogen as barley. Assuming both plants to derive 
their nitrogen from the soil (which is, perhaps, not quite 
correct in the case of peas), then for every milhgramme 
of nitrogen absorbed by the roots of the barley from the 
arable surface soil, twice as much must be received by 
the peas from the deeper layers. 

These considerations throw some light, I think, upon 
the cultivation of peas ; for this plant requires a very 
peculiar condition of the soil ; and it is more easy to con- 
ceive that a ground exhausted by bearing peas should 
refuse to bear any more, than that the same soil, after the 
lapse of some years, should again become fruitful for this 
plant. 

According to these considerations, and assuming an 
equahty of the absorbent root- surface in both plants, a 
subsoil fruitful for peas must contain as much phosphoric 
acid, and twice as much nitrogen, as an arable surface soil 
suited for the cultivation of barley. For the phosphoric 
acid, the assumption is correct. 

We imderstand, without difficulty, the beneficial effect 
of manure upon an exhausted barley field. Barley derives 



J 56 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 

all the conditions of healthy growth from the surface soil, 
which is restored to its original state of productiveness 
by the manure applied. 

But from our acquaintance with the properties peculiar 
to arable soil, we know that a layer 6 to 10 inches 
deep will retain all the ammonia potash and phosphoric 
acid contained in the largest quantity of manure usually 
applied by farmers ; and this, too, so hrmly that, except 
for some accidentally favourable circumstances, hardly a 
particle will ever reach the subsoil. 

If a field is sown with plants which require deep 
ploughing, so that a sufficient portion of the rich surface 
is mixed with the exhausted subsoil, it is easy to under- 
stand that the latter may gradually become again fruitful 
for peas. The time in which this is effected depends of 
course upon the accidental selection of the plants grown 
in succession on the field. 

In this view of the matter, the agriculturist has it in his 
power, by right management of his field, to shorten the 
time, and make the land again fit for successive crops of 
peas. 

It is a fact, that many fields in the vicinity of towns 
will bear year after year, or every two years, abundant 
crops of peas, without ever becoming ' pea-sick ; ' and we 
know that the gardener, to achieve this result, has re- 
course to no extraordinary appliances, but merely tills his 
land deep and very carefully, using much more maum-e 
than the farmer can afford to do. 

The frequent failure of peas is therefore not so very 
unaccountable ; and there seems no reason why the far- 
mer should despair of cultivating peas as often as serves 
his purpose, if he employ the right means to enrich his 
field in the proper spots with the elements of food which 
peas require. 



A CLOVER-SICK FIELD. 157 

In all problems of this kind, the secret of success is, 
not to suppose that the solution is easy, but that it is 
attended with great difficulties ; for, if these did not 
exist, experimental art would long ago have found the 
solution. 

The many unsuccessful experiments of Messrs. Lawcs 
and Gilbert to make a clover-sick field again productive 
for clover, have a certain value, in as far as they show 
that mere experimenting leads to nothing. If I here 
bestow upon these experiments an attention which they 
do not deserve, my object is, not to submit them to a 
passing criticism, but to warn the practical man how he 
ought not to proceed in trying to solve his problems, if 
he wishes that his efforts should meet with success. The 
conclusions which Messrs. Lawes and Gilbert have drawn 
from their numerous experiments are as follows : — - 

They found that when land is not yet clover-sick, the 
crop may frequently be increased by manuring with salts 
of potash and superphosphate of lime ; that when, on 
the contrary, the land is clover-sick, none of the ordinary 
manures, whether ' artificial' or ' natural,' can be rehed 
upon to secure a crop ; and that the only way is to wait 
some years before repeating red clover on the same land. 

It is hardly necessary to remark, that what Messrs. 
Lawes and Gilbert are here pleased to call conclusions, 
are no conclusions at all ; what they have discovered 
has been experienced by thousands of agricultmists 
before them ; and the only conclusion which they were 
permitted to draw should have been this — that in their 
attempts, by certain manures, to make a clover-sick field 
again productive for clover, they failed. In truth, they 
have not striven, in the remotest degree, to procure infor- 
mation about the causes of clover-sickness in a field, but 
they have simply tried different manures, in the hope of 



158 ACTIOX OF SOIL ON FOOD OF PLANTS IN MANURE. 

finding out one that miglit serve to restore tiie original 
productive power of tlie field, and such a manure they 
have not found. 

Messrs. Lawes and Gilbert assume that, with respect to 
the soil, the clover plant bears the same relation as wheat 
or barley; and finding that on a field (whereon, notwith- 
standing the richest manure, clover had failed) an abun- 
dant barley or wheat crop was obtained the year after, it 
became a settled conviction with them that the failure of the 
clover had been caused by a specific disease generated in 
the soil by the cultivation of clover ; this disease would 
attack the clover plant, but not the roots of wheat or 
barley. 

Clover differs entirely from the cereal plants in this 
respect, that it sends its main roots perpendicularly down- 
wards, when no obstacles stand in the way, to a 
depth which the fine fibrous roots of wheat and barley 
fail to reach; the principal roots of clover (as may be 
seen more especially with Trifolium pratense) branch off 
into creeping shoots, whicli again send forth fresh roots 
downwards. 

Thus clover, like the pea plant, derives its principal food 
from the layers below tlie arable surface soil ; and the 
difference between the two consists mainly in this — that 
the clover, from its larger and more extensive root-sur- 
face, can still find a sufficiency of food in fields where 
peas will no longer thrive : tlie natural consequence is, 
that the subsoil is left proportionably much poorer by 
clover than by the pea. 

Clover-seed, on account of its small size, can furnish 
from its own mass but few formative elements for the 
young plant, and requires a rich arable surface for its 
developement ; but the plant takes comparatively little 
food from the surface soil. When the roots have pierced 



A GLOVEK-SICK FIELD. 159 

tlirougli this, the upper parts are soon covered with a 
corky coating, and only the fine root-fibres ramifying 
through the subsoil convey food to the plant. 

Now, if we look at the experiments made by Messrs. 
I. awes and Gilbert to render a clover-sick field pro- 
ductive again for clover, we see, at once, that all the 
means employed vfere well adapted to enrich the upper- 
most layers of their field with nutritive substances for 
wheat and barley ; but that the clover plant could derive 
benefit from this manuring only in the first stage of 
developement, while the condition of the lower layers 
remained unaltered, just as if the field had received 
no nutriment of any kind. 

The manures apphed by Messrs. Lawes and Gilbert 
were superphosphate of lime (300 lbs. of bone-earth and 
225 lbs. of sulphuric acid per acre); sulphate of potash 
(500 lbs.); sulphate of potash and superphosphate, mixed 
alkaline salts (500 lbs. of sulphate of potash, 225 lbs. 
of sulphate of soda, 100 lbs. of sulphate of magnesia) ; 
mixed alkalis with superphosphate ; further, salts of 
ammonia alone, and the same salts with superphosphate 
or mixed alkalis ; farm-yard manure (15 tons), together 
with lime, or with lime and superphosphate, or with lime 
and alkalis in the most varied proportions ; then soot ; 
soot with lime ; soot with lime, alkalis, and superphos- 
phate. None of these manures had the shghtest effect ; 
the clover-sick field continued just as unproductive for 
clover as before. 

The reason why these manures were inoperative is 
not difficult to find. Messrs. Lawes and Gilbert, in their 
report, leave us, indeed, in the dark as to the nature 
and condition of the soil upon wdiich their experiments 
were made ; but from some incidental observations in 
previous papers, we know that the fields at Eothamstead 



160 ACTION OF SOIL ON FOOD OF PLANTS IN MANUEE. 

Gonsist of a rather heavy loam, very well suited for 
cereals, and especially for barley. 

From experiments upon the absorptive power of loam, 
we may assume, without risk of error, that one cubic 
decimetre (==61 cubic inches of loam) will absorb 2000 
miUigrammes ( = 31 grains of potash), and 1000 milli- 
grammes ( = 15-5 of phosphate of lime). 

The surface of an acre of loam (=405,000 square 
decimetres) will therefore absorb to a depth of 1 deci- 
metre (=4 inches) 805 kilogrammes ( = 1,771 lbs.) of 
potash, and 405 kilogrammes (= 891 lbs.) of phosphate 
of lime. 

The most copious dressing with sulphate of potash 
Avhich Messrs. Lawes and Gilbert gave to their field 
amounted to 500 lbs. (=270 lbs.) of potash; the most 
copious of the superphosphate dressings represented 
300 pounds of phosphate of hme. 

Had Messrs. Lawes and Gilbert put upon the field the 
sulphate of potash and the phosphate of lime in a state 
of complete solution, the whole quantity of potash em- 
ployed would have penetrated no deeper than 2 centi- 
metres, or not quite an inch, and the phosphate of lime 
no deeper than 4 centimetres, or a little more than 1*6 
inch. Both manures, however, were strewed over the 
field and ploughed in ; still it cannot be assumed that the 
layers below a depth of 8 inches could have received 
any considerable quantity of potash or phosphate of lime. 

At page 10 of their paper (' Eeport of experiments on 
the growth of red clover by different manures') Messrs. 
Lawes and Gilbert say, ' Those who have paid attention 
to the spread of disease in clover, on land which is said 
to be clover-sick, will have observed, that however luxu- 
riant the plant may be in the autumn and winter, it will 
show signs of failure in March or April.' The same fact 



CAUSE OF THE PAILUKE OF CLOVER. 161 

was observed in all tlieir experiments. A field on which 
clover had failed was sown with barley, and when this 
had yielded a rich crop, another attempt was made with 
■clover. 

' The plants (say Messrs. Lawes and Gilbert) stood 
tolerably well during the winter, but as the spring 
advanced they died off rapidly.' There cannot be the 
slightest doubt about the reason of this decay; the ex- 
hausted subsoil had not received back any of the lost 
conditions of fertility, and thus the plants were starved 
as soon as they had pushed through the arable surface 
soil, and their roots were beginning to spread in the subsoil. 

If the failure of the clover was attributable to a 
disease, this must have been of a very singular nature, 
as the richly-manured arable soil showed no traces of 
it, and it was only the subsoil which was clover-sick. 
The notion that there is any disease engendered by the 
cultivation of clover is refuted most completely, though 
unconsciously, by Messrs. Lawes and Gilbert themselves. 
They say, page 17, 'Before we enter upon the probable 
causes of the failure in clover, it may be well to give the 
results of some experiments conducted in the kitchen- 
garden at Eothamstead. The soil was in ordinary garden 
cultivation, and has probably been so for two or three 
centuries. Early in 1854, the j^th of an acre (about 
9£ square yards) was measured off and sown with red 
clover on March 29. From that time to the end of 1859 
fourteen cuttings have been taken without any resowing 
of seed. In 1856 this little plot was divided into three 
equal portions, of which one was manured with gypsum, 
another with sulphates of potash, soda, and magnesia, and 
superphosphate of hme.' 

' The estimated total amount of green clover obtained 
from this garden soil in six years, without further manure, 

M 



1G2 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 

is about 126 tons per acre, equal to about 26^ tons of 
hay. In four years the increase by the use of gypsum 
amounted to 15-| tons of green clover. The increase in 
the four years by the use of the alkalis and phosphate is 
estimated to amount to 28£ tons of green produce.' 

' It is worthy of remark,' continues the report, ' that 
it was in some of the very same seasons in which these 
heavy crops of clover were obtained from the garden 
soil, that we entirely failed to get anything like a mode- 
rate crop of clover in the experimental field, only a few 
hmidred yards distant.' 

It is, indeed, most worthy of remark, that upon the ex- 
perimental field the earth was poisoned by the vegetation 
of the clover, so as to render it incapable of further bear- 
ing this plant ; while, at the very same time, under hke 
climatic conditions, the self-same clover-plant engendered 
no poison in the rich garden soil. 

A comparative examination of the garden and of the 
field-soil seems never to have been thought of, since the 
two agricultural chemists were, as we before remarked, 
in search of an efficient manure, not of the cause of the 
failure of the plant. But though they have not found 
the smallest shred of a fact which might serve in any way 
to explain the strange behaviour of the clover-plant upon 
the two fields, they do not hesitate to present the farmer 
with the following ingenious explanation : — 

' Among plants,' say they, ' there are certain kinds 
which are peculiarly circumstanced with respect to the 
nature of their food ; the cereals, among others, feed 
principally upon inorganic matters, whilst others, the legu- 
minous plants, e.g. clover, are dependent for luxuriant 
growth, more or less, upon a supply within the soil of 
complex organic compounds.' 

Taking their stand upon the fact that they have failed 



EXPLANATION OF THE FAILUEE OF CLOVER. 163 

to discover any explanation, whicli, in their opinion, they 
surely must have clone, had it been possible to find 
one, they coolly ask us to believe that there are, among 
the higher classes of plants, certain species bearing about 
the same relation to other species as the carnivorous to 
the graminivorous animals ; and as the former feed upon 
complex organic compounds prepared in the bodies of 
the latter, so it is, also, with the clover plant ; like mush- 
rooms, it represents the carnivorous order in the vege- 
table kingdom. 

It is hardly worth while to take any notice of this ex- 
planation ; but it might still prove useful to inquire 
whether, apart from all consideration of the absorptive 
power of the soil, Messrs. Lawes and Gilbert have really 
exhausted all the means that might have been employed 
to restore the productiveness of the clover-sick field for 
clover, so as to be justified in giving it as their opinion 
that when land is clover-sick, none of the ordinary 
manures, artificial or natural, can be rehed upon to secure 
a crop. 

We may ask why Messrs. Lawes and Gilbert did not, 
instead of superphosphate of hme, try bone ash, the action 
of which extends much deeper than that of the super- 
phosphate; and why sulphate of potash and sulphates 
alone were employed ? It is not impossible that common 
wood ashes might have proved more effective than sul- 
phate of potash ; and, above all, chloride of potassium 
ought to have been tried, which, as an ingredient of liquid 
manure, is more useful to clover than any other of the 
potash salts. It is also difiicult to understand why liquid 
manure was not employed, and wlij chloride of sodium 
was excluded from the list of manuring agents. If we 
consider what Messrs. Lawes and Gilbert omitted to do in 
their endeavour to solve the problem, and what they 



164 ACTION OF SOIL ON FOOD OF PLANTS IN MANUKJi. 

ought to have done, the condusion is inevitable, that they 
had no accurate notion of the nature of their task. 

T^ow, the want of a proper insight into the nature of a 
phenomenon which is to be investigated is surely the 
greatest of all difficulties in the way of attaining a practical 
result. If the unproductiveness of a field for clover and 
peas depends upon a want of nitrogenous food in the 
deeper layers of the soil, and upon no other cause, the 
absorptive power of the various soils for ammonia renders 
it extremely difficult to enrich the subsoil with this ele- 
ment of food. But the case is quite different with the 
nitrates, which penetrate to any depth, as the nitric acid 
is not absorbed by the soil ; probably, nitrate of soda may 
afford a means of making a field productive for clover or 
peas, in cases where there is a deficiency of nitrogenous 
food. 

As manuring with burnt lime is often found beneficial 
for clover and also for peas, and a calcareous soil tends, 
in a special degree, to promote the formation of nitric 
acid, it is not improbable that it is owing to this property 
that lime promotes the growth of deep-rooting plants by 
converting ammonia into nitric acid, and causing nitro- 
genous food to find its way to the deeper layers of the 
soil. 



165 



CHAPTEE IV. 

FARM-YARD MANURE. 

The fertility of a soil depends upon the sum of available food, the continu- 
ance of the fertility upon the total amount of all food in it — Chemical 
and agricultural exhaustion of the soil — Exhaustion of the soil by culti- 
vation, laws regulating its progression; effect of the transformation in 
the soil of the chemically fixed into physically fixed elements of food ; 
effect on the progress of exhaustion by partial restoration of the with- 
drawn food of plants — Progress of the exhaustion by different cultivated 
plants — Cultivation of cereals, consequence of removing the grain and 
leaving the straw in the soil; intervening clover and potato crops; 
effect of leaving in the ground the whole or a portion of these crops ; 
division of soils ; productive power of wheat fields increased by accumu- 
lating in them the materials derived from clover and potato fields : cul- 
tivation of fodder plants ; their food partly derived from the subsoil ; 
addition of these increases the productive power of the sm'face soil — 
Natural connection between the cultivation of cereals and fodder plants, 
the influence on the fertility of land — Exhaustion of the soil removed 
by the restoration of the withdrawn mineral constituents ; the excrement 
of men and animals contains these ; their restoration depends upon the 
agriculturist. 

TO form a correct idea of the effects produced by farm- 
yard manure in husbandry, it must be remembered 
that the fertihty of a soil is always exactly proportionate 
to the amount which it contains of nutritive substances in 
a state of physical combination ; and that the permanence 
of its fertility or its productive power stands in proportion 
to the total quantity of the constituents in the soil capable 
of passing over into that physical condition. 

The amount of crop reaped from a field in a given 
time is proportionate to tliat fraction of the total con- 
stituents which has passed during this time from the 



166 FARM- YARD MANURE. 

ground into tlie plants grown upon it. If one of two 
fields yields twice as large a crop of wlieat and straw as 
the other, this necessarily presupposes that the wheat- 
plants upon the one field have received from the ground 
twice as much nutriment as those upon the other. 

If the same or different plants are cultivated in succes- 
sion on a field, the crops will gradually decrease, and the 
soil will be termed ' exhausted,' in an agricultural sense, 
when the crops cease to be remunerative, i. e. do not cover 
the expense of labour, interest of money, &c. As the 
high crops were caused by the soil giving to the plant a 
certain number of parts from the total nutritive substances, 
just so the exhaustion of the field proceeds from a diminu- 
tion in the sum of those nutritive substances. 

The same number of plants cannot thrive upon the 
same field as formerly, if the same quantity of nutritive 
substances enjoyed by the previous crop is no longer to be 
found. The exhaustion of a cultivated field in a chemical 
sense differs from the agricultural use of the term in this, 
that the former refers to the total amount of nutritive 
substances in the soil, the latter to that portion only of 
the total amount which the ground can furnish to plants. 
A field is termed exhausted in a chemical sense when it 
altogether fails to produce any more crops. 

Of two fields, one of which contains, to the same depth, 
a hundred times, the other only thirty times, the amount 
of food required by a full wheat crop, the former furnishes 
to the roots of the plants more nutriment than the latter 
in the proportion of 10 : 3, supposing the condition and 
mixture of the soil to be the same in both cases. If the 
roots of a plant receive from certain spots of the one field 
10 parts by Aveight of nutriment, the roots of the same 
plant will find upon the other field only 3 such parts 
available for absorption. 



DIMINUTION OF FOOD IN A WHEAT SOIL. 167 

An average wheat crop of 2000 kilogrammes (=39 
cwts.) of grain, and 5000 kilogrammes (=98 cwts.) of 
straw, receives from a hectare (=2^ acres) of ground 250 
kilogrammes (=5 cwts.) of ash constituents, on an average. 
Now, upon the supposition that a field, to give an average 
crop, must contain 100 times that quantity (or 25,000 
kilogrammes) of ash constituents in a perfectly available 
state, it follows that such a field gives 1 per cent, of its 
total store to the first crop. 

The soil will still continue productive for new wheat 
crops in the following years ; but the amount of produce 
will gradually decrease. 

If the soil is most carefully mixed, the wheat plants 
will, in the next year, find everywhere upon the same 
field 1 per cent, less nutriment, and the produce in corn 
and straw must be smaller in the same proportion. If 
the climatic conditions, the temperature, and the fall of 
rain remain the same, there will be reaped from the field 
in the second year only 1980 kilogrammes of grain, and 
4950 kilogrammes of straw ; and in each succeeding year 
the crop must fall off in a fixed ratio. 

If the wheat crop in the first year took away 250 kilo- 
grammes of ash-constituents, and the soil contained per 
hectare to the depth of 12 inches one hundred times that 
quantity (25,000 kilogrammes), there would remain in 
the ground at the end of the thirtieth year of cultivation 
18,492 kilogrammes of nutritive substances. 

Whatever variations in the amount of produce may 
have been caused by climatic conditions during the inter- 
vening years, it is evident that in the thkty-first year, if 
there has been no restoration of mineral matters, the 
field will produce, even under the most favourable cir- 
cumstances, only i|.^=0-74, or somewhat less than three- 
fourths of an average crop. 



168 PAEM-YAED MAJ^UEE. 

If these three-fourths of an average crop do not give 
the farmer a sufficient excess of income over expenditure, 
if they barely cover his outlay, the crop can no longer be 
called remunerative. He calls his field ' exhausted ' for 
the cultivation of wheat, although it contains seventy-four 
times the quantity of nutritive substances required by an 
average crop for the year. Owing to the presence of the 
entire sum of nutritive substances, in the first year of cul- 
tivation each root found, in the parts of the soil in 
contact with it, the requisite amount of mineral food for 
its complete developement ; but, owing to the continuous 
crops, only three-fourths of this quantity is found in the 
thirty-first year in the same portions of the soil. 

An average crop of rye (1600 kilogrammes (=31^ 
cwts.) of grain, and 3800 kilogrammes (=74^ cwts.) of 
straw) takes away from the ground per hectare only 180 
kilogrammes ( = 3^ cwt.) of ash-constituents. 

If the production of an average wheat crop requires 
the presence in the soil of 25,000 kilogrammes of the 
ash-constituents of wheat plants, a soil with only 18,000 
kilogrammes of such constituents will prove sufficiently 
rich to give an average and a succession of remunerative 
crops of rye. 

By our reckoning, a field, though exhausted for the 
cultivation of wheat, still contains 18,492 kilogrammes of 
mineral constituents, the same in properties as those 
which the rye plant requires. 

If it is asked after how many years continuous rye- 
cultivation the average crop will sink down to a three- 
quarter crop, assuming this to be no longer remunerative, 
we find that the field will produce 28 remunerative rye- 
crops, and after 28 years will be exhausted for its cultivation. 

The nutritive substances yet remaining in the soil will 
still amount to 13,869 kilogrammes of ash-constituents. 



EEMUNEEATIVE OAT CEOP AFTEE EYE. 169 

A field on which rye can no longer be cultivated with 
profit is not on that account unfruitful for oats. 

An average crop of oats (2000 kilogrammes (=39 
cwts.) of grain, and 3000 kilogrammes ( = 59 cwts.) of 
straw) takes from the soil 310 kilogrammes (=^6 cwts.) 
of ash-constituents, being 60 kilogrammes ( = 1-2 cwt.) 
more than is removed by a wheat crop, and 130 kilo- 
grammes (=2^ cwts.) more than by a rye crop. If the 
absorbent root-surface of the oat plant were the same as 
that of rye, oats after rye would not yield a remunerative 
harvest ; for a soil supplying, for the production of a 
crop of oats, 310 kilogrammes out of a stock of 13,869 
kilogrammes, loses thereby 2-23 per cent, of its store of 
mineral constituents, whereas the roots of rye extract 
only 1 per cent. 

To produce a remunerative crop of oats after rye is 
only possible when the root-surface of the oat plant 
exceeds that of the rye in the proportion of 2-23 to 1. 

Oat crops will therefore exhaust the soil the most 
speedily ; after 12| years the harvest will sink to three- 
fourths of the original amount. 

None of the causes tending to diminish or increase the 
crops have any influence on this law of exhaustion of the 
soil by cultivation. Whenever the stock of nutriment has 
been lowered to a certain point, the ground ceases to be 
productive, in an agricultural sense, for cultivated plants. 

For every cultivated plant such a law exists. This 
state of exhaustion will inevitably take place, even though 
only a single one of the various mineral constituents 
required for the nutrition of the plants has been with- 
drawn from the soil by a succession of crops ; for the one 
constituent which fails or is deficient renders all the rest 
ineffective. With each crop, each plant, or portion of a 
plant, taken away from a field, the soil loses part of the 



170 FARM-YAED MANUEE. 

conditions of its fertility, that is, after a course of years of 
cultivation it loses the power of again producing this crop, 
plant, or part of a plant. A thousand grains of corn require 
from the soil a thousand times as much phosphoric acid as 
one grain ; and a thousand straws demand a thousand times 
as much silicic acid as one straw. When, therefore, the 
soil is deficient in the thousandth part of phosphoric or 
sihcic acid, the thousandth grain or the thousandth straw 
will not be formed. If a single stalk of corn is taken 
away from a field, the consequence is that the field no 
longer produces one straw in its room. 

Hence it follows that a hectare of ground, containing 
25,000 kilogrammes of the ash-constituents of wheat, 
uniformly distributed, and presented to the roots of the 
plants in a perfectly available condition, can, up to a 
certain point, continue to give in succession remunerative 
crops of various cereal plants, without receiving any 
restoration of the mineral constituents taken away in the 
corn and straw, provided that the uniform mixture of the 
soil be maintained by careful ploughing and other suit- 
able means. The succession of crops is determined by 
this principle, that the second plant must always take 
away from the soil less than the first, or possess a greater 
number of roots, or generally a larger absorbent root- 
surface. After the average crop of the first year, the 
crops would go on yearly diminishing. 

The farmer, to whom uniform average harvests are the 
exception, and an alternation of good and bad crops 
dependent upon change of weather is the rule, would 
hardly notice this constant diminution, even supposing his 
field to be actually in that favourable chemical and 
physical condition which would enable him to cultivate 
wheat, rye, and oats for seventy years in succession, 
without restoring any of the mineral constituents removed 



UNEQUAL DISTRIBUTION OF FOOD IN SOILS. l7l 

from tlie soil. Good crops ptpproaching the average in 
favourable years, would alternate with deficient crops in 
bad seasons ; but the proportion of unfavourable to 
favourable returns would go on increasing. 

Most of the land under cultivation in Europe is not in 
the physical condition assumed in the case of the field 
which we have been considering. 

In most fields the phosphoric acid required by the 
plants is not all distributed in an effective condition, and 
accessible to the roots ; a part of it is merely disseminated 
through the soil in the form of smaU granules of apatite 
(phosphate of hme) ; and even where the soil contains 
altogether a quantity more than sufiicient, yet in some 
parts of it there is much more and in others less than the 
plants require. 

If we suppose our field to contain 25,000 kilogrammes 
of the ash-constituents of wheat equally distributed 
through the soil, and five, ten, or more thousand pounds 
of the same constituents, unequally distributed, the phos- 
phoric acid as apatite, the silicic acid and potash as 
decomposable silicates ; and, further, if every two years a 
certain quantity of this second portion of food elements 
becomes, in the manner stated, soluble and distributable, 
so that the roots of plants in all parts of the arable 
soil could find as much of these nutritive substances 
as in the preceding years of cultivation — sufiicient, there- 
fore, for an average crop ; we should, in that case, be able 
to obtain fall average crops for a number of years by 
always letting a year of fallow intervene after a year of 
cultivation. Instead of thirty progressively decreasing 
crops, we should in that case reap thirty full average crops 
in sixty years, if the excess of mineral matter in the soil 
were sufiiciently large to replace everywhere the phos- 
phoric acid, silicic acid, and potash taken away in each 



172 FAKM-YARD MANURE. 

year of crops. After the exhaustion of this excess of 
mineral matter, the period of diminishing crops would 
commence for our field, and the interposition of fallow 
years would, after this, no longer exercise the least influ- 
ence on the production of larger crops. 

If the excess of phosphoric acid, silicic acid, and 
potash, which we have assumed in the case under consi- 
deration, were not unequally but uniformly distributed, 
and everywhere perfectly accessible and available to the 
roots of the plants, our field would be able to yield 
thirty full average crops in thirty successive years, with- 
out the intervention of a season of fallow. 

Let us return to our field, which we have assumed to 
contain 25,000 kilogrammes of the ash-constituents of 
wheat, equally distributed through the soil, and in a suit- 
able state for absorption by the roots. Suppose we were 
to cultivate wheat upon it year after year, but instead of 
removing the entire crop we were merely to ciit off the 
ears, leaving the straw on the ground and immediately 
ploughing it in ; the loss sustained by the field would, in 
this case, be less than before, as all the constituents of the 
straw and the leaves would be left in the field, the mine- 
ral constituents of the grain alone having been removed. 

The straw and leaves contain, among their constituent 
elements, the same mineral substances as the grain, only 
in different proportions. If the total quantity of phos- 
phoric acid conveyed away in the straw and corn be 
designated by the number 3, the loss will be only 2, if 
the straw is left in the ground. The decrease of produce 
from the field, in tlie following year, is always in propor- 
tion to the loss of mineral substances occasioned by the 
preceding crop. The next produce of grain will be a 
little larger than it would have been had tlie straw not 
been left in the ground ; the produce of straw will be 



EETAEDATION OF THE PERIOD OP EXHAUSTION. 173 

nearly the same as in the preceding year, because the 
conditions for the formation of straw have been but 
slightly altered. 

Thus then, by taldng away from the ground less than 
formerly, we increase the number of remunerative crops, 
or the sum total of grain produced in the whole series of 
corn harvests. Some of the straw-constituents are con- 
verted into corn-constituents, and are now removed from 
the field in the latter form. The period of final ex- 
haustion, though sure to come in the end, will, under 
these circumstances, occur later. The conditions for the 
production of grain go on continually decreasing, because 
the substances removed in the corn are not replaced. 

It would make no difference in this respect, if the 
straw were cut and carted about the field, or used as 
fitter for cattle, and then ploughed in ; the supply thus 
bestowed upon the field, having been originally taken 
from the field, cannot enrich it. 

Considering that the combustible elements of the 
straw are not supplied by the soil, it is clear that in 
leaving the straw in the ground we leave nothing more 
than the ash-constituents of the straw. The field re- 
mained somewhat more fruitful than before, because a 
little less had been taken away. 

If the corn or its ash-constituents were ploughed 
in with the straw, or if, instead of it, a correspond- 
ing quantity of some other seed containing the 
same ash- constituents as wheat, e. g. ground rape-cake, 
that is, rape-seed freed from the fatty oil, were given 
in proper proportion to the ground, its composition 
would remain the same as before : the next year's crop 
would equal that of the preceding year. If after every 
harvest the straw is always in this manner returned to 
the field, the further consequence will be an inequality in 



174 FARM-YAED MANUEE. 

the composition of the effective constituents in the arable 
soil. 

We have supposed our field to contain the ash-con- 
stituents of the entire wheat plant in proper proportion 
for the formation of straw, leaves, and grain. By leaving 
the straw-constituents in the ground, while continuaUy 
removing the grain-constituents, the former will accu- 
mulate and grow out of due proportion to the remainder 
of the grain-constituents still contained in the field. The 
field retains its fertility for straw, but the conditions re- 
quired for the production of grain are diminished. 

The consequence of this disproportion is an unequal 
developement of the entire plant. As long as the soil 
contained and supplied the right proportion of ash con- 
stituents needful for the uniform growth of all parts of the 
plant, so long the quality of the seed and the ratio between 
straw and corn in the diminishing crops remained con- 
stant and unaltered. But, in proportion as the conditions 
for the production of leaves and straw became more 
favourable, the quality of the grain deteriorated with its 
decreasing quantity. The distinctive mark of this in- 
equality in the soil, resulting from cultivation, is a decrease 
in the weight of the bushel of corn reaped from the field. 
At first a certain quantity of the constituents restored to 
the soil in the straw (phosphoric acid, potash, magnesia), 
was expended in the formation of grain ; but afterwards 
the case is reversed, and the grain-constituents (phosphoric 
acid, potash, magnesia) are drawn upon for the production 
of straw. The condition of a field is conceivable where 
by reason of inequality in the relative conditions for pro- 
ducing straw and grain, under temperatm-e and moisture 
favourable for the formation of leaves, a cereal plant 
may yield an enormous crop of straw, with empty ears. 

The farmer, in cultivating his plants, can act upon the 



EXHAUSTION OF A WHEAT SOIL. 175 

direction of the vegetative force only tlirougli the soil, i.e. 
by supplying his field with nutritive substances, in the right 
proportions. For the production of the largest crop of 
grain, the soil must contain a preponderating quantity of 
the nutritive substances necessary for the formation of 
seed. For leafy plants, turnips, and tuberous plants, the 
proportion is reversed. 

It is therefore evident, that if on our field containing 
25,000 kilogrammes of the ash-constituents of the wheat- 
plant, we cultivate potatoes and clover, and take away 
from the field the entire crop of tubers and clover, we 
remove from the ground, in these two products, as much 
phosphoric acid and three times as much potash as in 
three wheat crops. It is certain that the abstraction of 
these important mineral constituents from the ground, by 
the cultivation of another plant, must greatly affect the 
fertihty of the soil for wheat ; the crops of wheat diminish 
in amount and in number. 

But if, instead of this, we were to cultivate on our 
field alternately, wheat one year, potatoes the next, 
leaving the entire potato crop, tubers included, and the 
wheat straw on the ground to be ploughed in, and if this 
alternation of crops were continued for sixty years, the 
crop of corn which the field was originally capable of 
yielding would not in the slightest degree be altered or 
increased. The field would gain nothing by the culti- 
vation of potatoes ; and would lose nothing, because the 
whole crop was left in the soil. When by taking corn 
crops from the field, the store of mineral constituents had 
been reduced to three-fourths of the original quantity, the 
field would cease to furnish remunerative crops, supposing 
that three-fourths of an average harvest leave no margm 
of profit for the farmer. The same results would follow, 
if instead of potatoes we interpose clover, and constantly 



176 FAEM-YAED MANUEE. 

ploughed it in. We have assumed the field to be in the 
best physical condition, which therefore could not be 
improved by the incorporation of the organic substances of 
the clover and the potatoes. Even if we were to take the 
potatoes from the field, to mow down and dry the clover, 
giving both to cattle in the farm-yard or making any 
other use of them, and then to bring all back to the field and 
plough them in, so as to restore to the soil all the mineral 
constituents contained in both crops, yet by all these 
operations the field would not produce, in thirty, sixty, or 
seventy years, a single grain of corn more than with- 
out this alternation. The conditions required for the 
production of grain are not improved in the field during 
the whole of this period, and the causes of decrease in the 
crops remain the same. 

The ploughing in of the potatoes and the clover could 
have a beneficial effect upon those fields only which have 
an inferior physical condition, or in which the mineral 
constituents are unequally distributed, or are partially 
inaccessible to the roots of plants. But this effect is 
like that of green manuring, or of one or more years of 
fallow. 

By the incorporation of the clover and the organic con- 
stituents with the soil, its store of decaying substances 
and nitrogen increased year by year. All that these 
plants received from the atmosphere remained in the 
ground ; but the increase of these otherwise so useful 
substances cannot make the soil produce a larger amount 
of grain than before ; since the production of grain depends 
upon the right proportion of ash-constituents in the soil, 
and these, so far from being increased, have been gradually 
reduced by the removal of the corn crops. The aug- 
mentation of nitrogen and of decajring organic substances in 
the soil might possibly lead to an increase of produce foi 



GRADUAL EXHAUSTION OF A WHEAT SOIL. 177 

a number of years ; but the period when this field will 
cease to give remunerative crops will in that case come 
all the sooner. 

If we take three wheat fields, and cultivate wheat upon 
the one, potatoes and clover upon the other two ; and 
suppose we remove the corn alone from the wheat field 
and heap upon it and plough in all the crop of clover 
and all the potato tubers, then the wheat field will be 
more fertile than before, for it has been enriched by all 
the mineral constituents which the two other fields had fur- 
nished to the potatoes and the clover. It has received three 
times as much phosphoric acid and twenty times as much 
potash as was contained in the corn crop it produced. 

This wheat field wiU now be able to produce three fuU 
corn crops in three successive years, because the con- 
ditions for the formation of straw have remained unaltered, 
while those for the production of grain have been in- 
creased three-fold. If the farmer by this method raises 
as much corn in three years as he could obtain from the 
same fields in five years without the addition and co- 
operation of the constituents contained in the clover and 
the potatoes, it is clear that Ins profit has been greater, 
since with three seed-corns he has obtained as good a 
harvest as in the other case with five. But what the 
wheat field has gained in fertiUty, the other two fields 
have lost ; and the final result is, that at less cost of 
cultivation, and with more profit than before, his three 
fields are brought to the period of exhaustion, which 
inevitably results from the continued removal of the 
mineral constituents in the crops of corn. 

The last case which we have to consider is when the 
farmer, instead of growing potatoes and clover, cultivates 
turnips and lucerne, which by their long penetrating- 
roots extract a great quantity of mineral constituents 



178 FAEM-YARD MANURE. 

from the subsoil, to whicli the roots of the cereals very 
seldom penetrate. When the fields have a subsoil favour- 
able to the growth of these plants, it is as though the 
arable surface soil were doubled. If the roots of these 
plants receive the half of their mineral nutriment from the 
subsoil, and the other half from the arable surface soil, 
the latter will lose by these crops only half as much as 
they would, if all the mineral constituents had been drawn 
by them from the surface. 

Thus the subsoil, considered as a field apart from 
the arable soil, gives to turnips and lucerne a certain 
quantity of mineral constituents. Now, if the whole of 
the turnip and lucerne crops were ploughed in during the 
autumn in a wheat field which had yielded an average 
crop of wheat, so that the field should receive back 
more than it had lost in the corn, it is clear that this 
field might be maintained in an equable state of fertility, 
at the expense of the subsoil, just so long as the latter 
remained productive for turnips and lucerne. 

As, however, turnips and lucerne requfre for their de- 
velopement a very great quantity of mineral constituents, 
the subsoil is so much the sooner exhausted, when it con- 
tains fewer of such constituents. Now as it is not actually 
severed from the arable surface, but hes underneath, it 
can scarcely regain any of all the constituents which it 
has lost, because the surface soil intercepts and retains the 
portion supplied. Only that part of the potash, ammonia, 
phosphoric acid, and silicic acid, which is not taken up 
and fixed by the surface soil, can reach the subsoil. 

It is tlicrefore possible, by the cultivation of these deep- 
rooting plants, to gain an abundant supply of nutritive 
substances for all plants drawing their nutriment chiefly 
from the arable soil ; but this supply is not lasting, 
and in a comparatively short time many fields will cease 



A SECOND CEOP DEPENDS ON THE PEECEDING ONE. 179 

to bear crops, because the subsoil is exhausted, and its 
fertility is not easily restored. 

If a farmer grows upon three fields, potatoes, corn, and 
vetches or clover, alternately, or if he cultivates one field 
with potatoes, corn, and vetches successively, selling the 
crops, and going on hi the same way for many years, 
without manuring, any one can foresee the end of such 
husbandry, because such a system cannot possibly last. 
No matter what plants may be selected, what variety of 
cereals, tuberous or other plants, or in what rotation, the 
field will at length be reduced to such a state that the 
cereals will yield no more than the seed sown, the 
potatoes will give no tubers, and the vetches or clover 
will die away after barely appearing above ground. 

From these facts it follows indisputably, that there is no 
plant wliich spares the ground, and none which enriches 
it. The practical farmer is taught by innumerable instances 
that the success of a second crop depends upon the pre- 
vious one, and that it is by no means a matter of indiffer- 
ence, in what order he cultivates his plants ; by previously 
cultivating some plant with extensive ramification of roots, 
the soil is made fitter for the growth of a succeeding cereal, 
which will now thrive better, even without the application 
of manure (with sparing application), and yield a richer 
crop. But this is not a saving of manure for future crops, 
nor has the field been enriched in the conditions of its 
fertihty. There has been an increase, not in the sum of 
the nutriment, but in the available particles of that sum, 
and their operation has been hastened in point of time. 

The physical and chemical condition of the field was 
improved ; but the store of chemical elements was 
reduced. All plants, without exception, drain the soil, 
each in its own way, and exhaust the conditions for their 
reproduction. 

N 2 



180 FARM- YARD MANURE. 

In the produce of his field the farmer actually sells his 
land ; he sells, in his crops, certain elements of the atmo- 
sphere, which come of themselves to his soil ; and with 
them certain constituents of the ground, which are his 
property, and which have served to form, out of the 
atmospheric elements, the body of the plant, being them- 
selves component parts of that body. In ahenating the 
crops of his field, he robs the land of the conditions re- 
quired for their reproduction. Such a system of husbandry 
may properly be called a system of spohation. 

The constituents of tlie soil are the farmer's capital ; the 
atmospheric nutritive substances are the interest of his 
capital ; with the former he produces the latter. In selling 
the produce, he alienates part of his capital and the 
interest ; in restoring the constituents of the soil to the 
ground, he retains his capital. 

Common sense tells us, and all farmers agree, that 
clover, turnips, hay, &c., cannot be sold off from a farm 
without materially damaging the productive power of the 
land for corn. 

Everyone wilhngly admits, that the removal of clover 
is prejudicial to the cultivation of corn ; but that the 
removal of corn should injure the cultivation of clover 
is to most farmers an inconceivable, nay, an impossible 
idea. 

Yet the natural connection and mutual relations be- 
tween the two classes of plants are as clear as daylight. 
The ash-constituents of clover and corn are the conditions 
for the formation of clover and corn, and are identical as 
far as the elements are concerned. 

Clover, just like corn, requires for its production a 
certain amount of phosphoric acid, potash, lime, and 
magnesia. The mineral constituents of clover are the 
same as those of corn, plus a certain excess of potash. 



COKN SOLD IS MANURE LOST. 181 

lime, and sulphuric acid. The clover draws these con- 
stituents from the soil, the cereal plants may be represented 
as deriving them from the clover. In selling his clover, 
therefore, the farmer takes away the conditions for the 
production of corn, and there remains behind in the soil 
less nutriment for the corn ; if he sells his corn, he takes 
away from the land some of the most indispensable con- 
ditions for the production of clover, hence the clover 
crop fails in a subsequent year. 

The peasant knows the operation of these fodder-plants, 
and expresses his views in his own way when he says, 
' that, as a matter of course, a man must not sell his 
manure, without which no permanent cultivation is 
possible, and that in selling the fodder-plants, a man sells 
his manure.' But that in selhng his corn, a farmer is still 
parting with his manure, does not seem to be understood 
by many even of the most enhghtened agriculturists. 
Earm-yard manure contains all the mineral constituents of 
fodder ; and these consist of the constituents of corn, plus 
a certain quantity of potash, hme, and sulphuric acid. It 
is quite evident, that as the whole dung-heap consists of 
parts, not one of those parts should be alienated ; and if 
it were possible, by any means, to separate the corn-con- 
stituents from the rest, they would possess the greatest 
value to the farmer, because upon them the cultivation of 
the corn depends. But this separation actually takes 
place in the growth of corn, as the mineral constituents of 
the manure become the constituents of the corn ; hence 
in selling the corn, the farmer alienates a portion, and 
indeed the most efficient portion, of his manure. 

Two dung-heaps, looking quite ahke, and apparently of 
the same quality, may yet have a very dissimilar value for 
the cultivation of corn. If in one heap the ash -con- 
stituents of corn are twice as many as in the other, the 



182 PARM-YAED MANURE. 

former has double the vahie of the other. By the removal 
of the mineral constituents of the corn, which were de- 
rived from the manure, the efficacy of the manure with 
regard to future corn crops is constantly diminished. 

From whatever point of view, therefore, the alienation 
of corn or other field produce may be regarded, the farmer 
who does not replace the mineral constituents taken away 
in the crops, will find that the inevitable result is exhaus- 
tion of the soil. Continued removal of the corn crops 
makes the ground unproductive for clover, or deprives the 
manure of its efficacy. 

In our exhausted fields the roots of cereals no longer 
find, in the upper layers of the soil, sufficient nutriment 
for the production of a full crop : the farmer, therefore, 
grows on these fields clover, turnips, and other plants of 
the kind, which, with their wide-spreading and deep 
roots, penetrate in all directions through the soil, open up 
the ground by their large root-surface, and appropriate 
the constituents which are needed by cereals for the for- 
mation of seed. In the residue of these plants, m the 
constituents of the stalks, the roots, and the tubers, 
which the farmer puts upon the arable surface in the 
form of manure, he restores to the land, in a concen- 
trated form, the corn constituents for one or several full 
crops : what was below and scattered, is now above. 
The clover and the fodder-plants did not engender the 
conditions of richer corn-crops, any more than rag- 
gatherers produce the conditions for paper-making ; they 
are mere collectors. 

From the foregoing remarks it is evident that the cul- 
tivation of plants exhausts the fertile soil, and renders it 
unfruitful. Li selling the produce of his fields, which 
serves as food for man and beast, the farmer removes a 
portion of his soil, and indeed the constituents most 



MUTUAL RELATION OF PLANTS AND ANIMALS. 183 

efficient for the production of future crops. In course of 
time, the fertihty of his fields will decrease, no matter 
what plants he cultivates, or what order of rotation he may 
adopt. The removal of his crops is nothing else than 
robbing the ground of the conditions for future harvests. 

A field is not exhausted for corn, clover, tobacco, or 
turnips, so long as it yields remunerative crops, without 
needing the replacement of those mineral constituents 
which have been Carried away. It is exhausted from the 
time that the hand of man is needed to restore the 
failing conditions of its fertihty. In this sense, most of 
our cultivated fields are exhausted. 

The hfe of men, animals, and 23lants is most intimately 
connected with the restoration of aU those conditions 
which cause the vital process to go on. The soil, by its 
constituents, takes part in the hfe of the plant ; its per- 
manent fertihty is inconceivable and impossible, without 
the replacement of those conditions which have made it 
productive. 

The mightiest river which sets in motion thousands of 
mills and machines must fail, if the streams and brooks 
supplying its waters run dry; so, too, the streams and 
brooks will run dry if the many little drops of which 
they consist fail to return in the form of rain to the 
place whence their sources spring. 

A field which, by the successive cultivation of different 
plants, has lost its fertility, may recover the power of 
yielding a new series of crops of the same plants, by the 
apphcation of manure. 

What is manure, and whence comes it ? All manure 
comes from the farmers' fields : it consists of straw, which 
has served as fitter ; of remains of plants, of the hquid 
and solid excrements of men and animals. The excre- 
ments are derived from food. 



184 FARM-YARD MANURE. 

In his daily bread, man consumes the ash-constituents 
of the grain from the flour of which bread is made : in 
meat he consumes the ash-constituents of flesh. 

The flesh of herbivorous animals, and its ash-consti- 
tuents, are derived from plants ; these ash-constituents 
are identical with those of the seeds in leguminous 
plants. Hence if an entire animal is burnt to ashes, the 
residue will differ httle from the ashes of beans, lentils, 
and peas. 

In bread and flesh, therefore, man consumes the ash- 
constituents of seed, or of seed-constituents which the 
farmer has obtained from his fields in the form of flesh. 

Of the large amount of mineral substances which man 
consumes in his food during a lifetime, but a small fraction 
remains in his body. The body of an adult does not 
increase in weight from day to day, which proves that all 
the constituents of his food must completely pass out 
again from his system. 

Chemical analysis demonstrates that the excrements 
of man contain the ash-constituents of bread and flesh 
very nearly in the same quantity as they exist in the 
food, which in the body undergoes a change similar to 
that which would take place in a furnace. 

The urine contains the soluble, the solid excrements 
the insoluble ash-constituents of food : the stinking sub- 
stances are the smoke and soot of an imperfect combus- 
tion. With these are mixed up the undigested and the 
indigestible remains of food. 

The dung of swine fed on potatoes contains the ash- 
constituents of the potato ; that of the horse, the ash- 
constituents of hay and oats ; that of cattle, the ashes of 
turnips, clover, and other plants which have served them 
as food. Farm-yard manure comprises a mixture of all 
these excrements. 



FERTILITY NOT DUE TO ORGANIC MATTER. 185 

That farm- yard manure will completely restore the fer- 
tiUty of a field exhausted by cultivation is a fact fully 
established by the experience of a thousand years. 

Farm-yard manure supplies to the field a certain quan- 
tity of organic, i. e. combustible substances, together with 
the ash-constituents of the food consumed. We must 
now consider what part is taken, in the restoration of 
fertility, by the combustible and incombustible consti- 
tuents of the manure. 

The most superficial examination of a cultivated field 
shows that all the combustible constituents of the plants 
grown upon it are derived from the air and not from the 
soil. If the carbon even of a portion of the vegetable 
matter in the crop were derived from the soil, it is quite 
clear, that if the ground contained a certain amount of 
carbon before the harvest, this amount must be smaller 
after every harvest. A soil deficient in organic matter 
must necessarily be less productive than a soil abounding 
in it. 

Now, experience proves that a field in constant culti- 
vation does not, therefore, become poorer in organic or 
combustible substances. The soil of a meadow which in 
ten years has yielded a thousand cwt. of hay per hectare, 
is found to be, at the end of those ten years, not poorer 
in organic substances, but richer than before. A clover- 
field after a crop retains in the roots left in the ground 
more organic substances, more nitrogen, than it originally 
possessed ; yet after a number of years it becomes 
unproductive for clover, and no longer gives remu- 
nerative returns of that crop. 

A field of wheat, or potatoes, is not poorer in organic 
substances after harvest, than before. As a general rule, 
cultivation increases the store of combustible constituents 
in the ground, while its fertility, however, steadily dimi- 



186 PAEM-TAED MANUKE. 

nishes. After a consecutive series of remunerative crops of 
corn, turnips, and clover, these plants will thrive no longer 
in the same field. 

Since, then, the presence of decaying organic remains 
in the soil does not, in the slightest degree, prevent or 
arrest its exhaustion by cultivation ; it is impossible that 
an increase of those substances can restore the lost capa- 
city of a field for production. In fact, when a field is 
completely exhausted, neither boiled saw-dust, nor salts 
of ammonia, nor both combined, will impart the power 
of yielding the same series of crops a second and third 
time. When these substances improve the physical con- 
dition of the ground, they exert a favourable influence 
upon the produce ; but, after all, their ultimate effect is 
to accelerate and complete the exhaustion of the soil. 

But farm-yard manure thoroughly restores to the soil 
the power of producing the same succession of crops a 
second, a third, and a hundredth time : where it is 
apphed in proper quantities it will fully cure the state 
of exhaustion, and often make a field more fertile than 
it ever was before. 

The restoration of fertihty by farm-yard manure Can- 
not be attributed to the mixture of combustible mate- 
rials (salts of ammonia and the substance of decaying 
saw-dust): for if these had a favourable effect, it must 
have been of a subordinate kmd. The action of farm- 
yard manure most undoubtedly depends upon the incom- 
bustible ash-constituents of the plants which it contains. 

In farm-yard manure the field actually receives a cer- 
tain quantity of all the mineral ingredients which have 
been removed in the crops. The decline of fertihty was 
in proportion to the removal of mineral constituents ; the 
renewal of productiveness is in proportion to their 
restoration. 



MINEEAL MATTEES EESTOEED BY MAN. 187 

The incombustible elements of cultivated plants do not 
of themselves retmm to the soil, as the combustible ele- 
ments return to the atmosphere from which they spring. 
The hand of man alone restores to the ground the condi- 
tions of the life of plants : in farm-yard manure wherein 
they are contained, the farmer, following a natural law, 
restores the lost power of production. 



188 



CHAPTEE Y. 

THE SYSTEM OP FAEM-YAED MANUEING. 

Questions to be solved — Experiments of Renning, their significance — 
Produce of unmanured fields — Influence of preceding crops, of the situ- 
ation, and climatic conditions, on the produce — Each field possesses its 
own power of production — Large crops, their dependence and continua- 
tion — Closeness of the food of plants, what is meant thereby — The 
closeness of the particles of food in the soil is in proportion to the pro- 
duce — Produce of corn and straw influenced by the relations of the 
assimilated food and by the conditions of growth ; action of food sup- 
plied in manures — Potatoes, oats, and clover crops of the Saxon fields ; 
conclusions drawn from them as to the condition of the fields — Produce 
of these fields from farm-yard manure ; the increase of produce cannot be 
calculated from the amount of manure used — Restoration of the power of 
production of exhausted fields by the increase of the necessary elements of 
food present in the soil in minimum amoimt; advantageous use of farm-yard 
manure in this respect ; explanation of the result — Action of manure as 
compared with quantity used : expei'iments — Rational system of cultivation 
— Depth to which the food of plants penetrates is dependent on the power 
of absorption of the soD. ; the Saxon fields considered in this respect ; the 
power of absorption considered in manuring — Change produced in the 
composition of the soil by the system of farm-yard manuring; the dif- 
ferent stages of this system, the final residt — Examples of these stages in 
the Saxon experimental fields — Cause of the growth of weeds ; reme- 
dies — The history of husbandry, what is taught by it — Present condi- 
tion of European husbandry — Present production of the land compared 
with the earlier; conclusions — Continuation of production regulated by 
a natural law — Law of restoration ; defective practice of it — Agricul- 
ture in the time of Charlemagne — Agriculture in the Palatinate — Corn 
fields in the valleys of the Nile and Gauges ; nature provides in them for 
the restoration of food of plants — Practical agricultm'e and the law of 
restoration — The statistical returns of average crops afibrd an explana- 
tion of the condition of corn fields. 

THE general observations in the preceding chapters 
on the mutual relations between the soil and plants, 
as also on the sources and nature of farm-yard manure, 
will, I hope, enable the reader to enter upon a thorough 



QUESTIONS TO BE CONSIDERED. 189 

investigation of all those phenomena which are presented 
by the practice of farm-yard manuring. We have to con- 
sider how farm-yard manure increases the produce of a 
field ; on which constituents of the manure its action de- 
pends ; what quantity of farm-yard manure can be obtained 
from a field ; and to what condition, after a series of years, 
a field can be restored by farm-yard manuring. 

It will be understood that from this investigation we 
exclude all those efiects of farm-yard manure which can- 
not be determined by measure and number ; such, for 
instance, as its influence upon the looseness or cohesion of 
the soil, and its heating action, by means of the warmth 
resulting from the decay of its constituents in the ground. 

The facts, to which this investigation extends, are de- 
rived from practical experience ; and my selection of them 
has been materially facilitated by the comprehensive 
series of experiments made in the year 1851, at the in- 
stance of Dr. Eenning, Secretary-General of the Agri- 
cultural Society in the kingdom of Saxony, by a number 
of Saxon agriculturists, with a view of ' ascertaining the 
action of so-called artificial manures under every variety 
of condition, for the purpose of more generally extending 
their application.' These experiments were continued to 
the year 1854, every series embracing a rotation of rye, 
potatoes, oats, and clover. The farmers were requested 
to try bone-dust, rape-cake meal, guano, and farm-yard 
manure, each on a Saxon acre (=1-36 Enghsh acre) of 
ground, compared with an unmanured plot of the same 
size, and to determine the respective crops by weight. 

Of all experiments of a similar nature which have 
been made in the course of several centuries, those which 
are expressly stated to have been undertaken ' without 
a direct scientific object' are of the highest scientific im- 
portance, not only for their very comprehensive character, 



190 



THE SYSTEM OF FAEM-YARD MANUEING. 



but because they have resulted in fully estabhsliing a 
number of facts which will for all time to come retain 
their validity as safe bases for scientific conclusions. 
Science owes the deepest gratitude to the excellent pro- 
pounder of these inquiries, and to the worthy men who so 
zealously performed their task ; the only thing to be 
regretted is, that the experiments upon unmanured plots 
were not carried out in all cases. 

It is evident that the action of farm-yard manure upon 
a field can be properly estimated only if it is known before- 
hand what amoimt of produce the field will give without 
any manure : and first of all we shall consider the crops 
produced on five fields in five different parts of Saxony, 
in the four-year rotation above mentioned. 



Crop 


"Unmanured 


Cminersdorf 


Mausegast 
Mixtm-e 


Kotitz 
Wliite Clover 


Oberbobritzsch 
Red Clover 


Obersobbna 
Grass 


1851 
Eye 

Grain 
Straw 

1852 
Potatoes . 

1853 

Oats 
Grain 
Straw . 

1854 
Clover-hay 


lbs. 

1176 
2951 

16667 

2019 
2563 

9144 


lbs. 

2238 
4582 

16896 

1289 
1840 

5583 


lbs. 

1264 
3013 

18577 

1339 
1357 

1095 


lbs. 

1453 
3015 

9751 

1528 
1812 

911 


lbs. 

708 
1524 

11095 

1082 
1714 



These results lead to the followhig considerations. 

The term unmanured, as applied to these fields, is 
meant to designate the condition in which they were left 
at the end of a rotation by a succession of crops. 

These fields had been manured at the beginning of the 
rotation ; and had they been manured afresh, they would 



THE SOIL AND THE PEODUCE. 191 

have produced the same crops as before. In the crops 
yielded by them in the manured state, the constituents of 
the soil and those of the manure had a certain definite 
share : if the fields had not been manured, the crops would 
have been smaller. ISTow if we attribute the increased pro- 
duce during the course of the rotation to the supply of 
farm-yard manure, and suppose that the constituents of the 
farm-yard manure have been again removed^in the crops, 
which is not true in all cases, then the field, at the end of 
the rotation, is in the same state in which it was at the 
commencement, before it had been manured. Accord- 
ingly, we may assume, without great risk of error, that 
the produce of different crops, which a plot of ground 
will yield in a new rotation without manuring, will be in 
proportion to the store of nutritive substances, ready for 
assimilation, which it contains in its natural state. Hence 
from the unequal products yielded by the two fields in 
that state, we may, with an approximation to truth, infer 
certain inequalities in the amount of food or in the con- 
dition of the fields. 

Of course, inferences of this kind are admissable only 
within very narrow limits ; for when we compare two 
fields which lie in the same or in different districts, we 
must remember that in each case various factors operate 
upon the products, making these unequal, even though 
the nature of the soil be otherwise identical. 

If, for instance, two fields, both unmanured, are planted 
with one and the same cereal, it is by no means a matter 
of indifference, as regards the produce of corn and straw, 
what crop has preceded the cereal. If the last crop in 
the preceding rotation was clover on the one, oats on the 
other field, the results wiU vary, even though the con- 
dition of the soil in both was originally identical ; and 
the produce reaped, in that case, indicates merely the 



192 THE SYSTEM OF FAEM-YARD MANURING. 

state into which the field has been brought by the pre- 
ceding crop. 

In hilly districts, a northern or southern aspect makes 
a difference in the comparative character of two fields ; so 
too does the height above the sea, on which the quantity 
of the fall of rain depends. A fall of rain received at a 
more favourable time by one field than by another makes 
a difference in the amount of produce, even though the 
condition of the soil be the same in both fields. 

Lastly, in judging, in the manner indicated, of the state 
and condition of a field, the weather during the preceding 
year must be taken into account. 

The crop produced by a field in a year is always the 
maximum crop which it can yield under the conditions 
given : under more favourable external circumstances, 
that is, with better weather, the field would have fur- 
nished a greater crop ; under more unfavourable circum- 
stances, a smaller, always corresponding to the condition 
of the soil. 

By the production of larger crops, in consequence of 
fa^^U^rable weather, the field loses a comparatively greater 
amount of nutritive substances, and the subsequent harvests 
show a dechne ; just as, on the other hand, deficient 
crops will act upon the yield of subsequent years, as a 
fallow year with half-manuring does, that is, the crops 
coming after bad years will turn out better, even in 
ordinary weather. 

The relative proportions of corn and straw, in a crop of 
cereals, are altered by a continuance of dry or wet weather. 
Permanent wet, combined with a high temperature, 
favours the .developement of leaves, stalks and roots ; and 
as the plant goes on growing, the materials intended for 
the production of seed are used for the formation of new 
shoots, and thus the seed crop is diminished. 



THE PRODUCTIVE POWER OP LAND VARIES. 193 

Continuous clrouglit, before or during sprouting time, 
produces the opposite effect ; the store of formative mat- 
ter accumulated in the roots is used in far greater propor- 
tion for the production of seed, and the relation of straw 
to corn is smaller than it would be in ordinary weather. 

When all these circumstances are taken into account, 
the consideration of the produce obtained from unmanured 
fields in the Saxon experiments will leave only a few 
general points for further investigation. 

The tabular statement of the result shows that each 
field has a power of production peculiar to itself, and 
that no two of them have produced the same amount of 
rye corn and straw, or potatoes, or oats and straw, or 
clover. 

If we compare the numberless manuring experiments 
of the last few years, in which the crops obtained from 
unmanured plots were likewise taken into account, we 
see that this is a general rule admitting of no exception : 
no two fields have exactly the same productive power ; 
nay, there are not even two plots in the same field which 
are identical in this respect. We need only look at a 
turnip field to see at once that every turnip differs in 
size and weight from the one growing next to it. This 
fact is so universally known and admitted, that in all 
countries where the land is taxed, the amount of the 
impost is assessed according to the quality of the soil, in 
some countries in eight classes, in others in twelve or 
sixteen. 

Since, then, no two fields are alike in productive power, 
and every field must necessarily contain the conditions 
required for the production of the crops which it yields, 
it is clear that the conditions for the production of corn 
and straw, or of turnips and potatoes, or of clover or any 
other plant, are in no two fields alike : in one field the 

o 



194 THE SYSTEM OF FAEM-YAED MANURING. 

conditions for the production of straw preponderate over 
those for the production of grain, another is better 
suited for the growth of clover, and so on. 

These conditions, according to their very nature, differ 
in quantity and quahty. By . conditions which can be 
weighed and measured, we of course mean no other than 
nutritive substances. 

The crops reaped from a field afford no indication of 
the quantity of nutritive substances in the ground. 
Consequently, the fact that the field at Mausegast gave 
twice as much corn and one-third more straw than the 
one at Cunnersdorf, cannot lead to the inference that the 
former was upon the whole richer in -these proportions 
in the conditions for the production of corn and straw ; 
for we see that the Cunnersdorf field gave two years 
after, without manuring, one-half more oat-corn and 
straw than the field at Mausegast, and in the fourth year 
above 60 per cent, more clover. Now some of the most 
important food elements of corn are as essential to clover 
as to the cereals ; and the food elements of oats are 
identical with those of rye. 

A larger crop of any of the cultivated plants given by 
one field over another merely indicates that the roots in 
the one field, in their way downwards, have found and 
absorbed in certain portions of the soil more particles of 
the whole store of nutritive substances contained in it in 
an available state than the roots in the other field ; but 
not that the total sum was greater in the one than in the 
other : for the field apparently poorer might in reahty 
have contained a much larger total amount of nutritive 
substances than the other, only not in a condition avail- 
able to the roots. 

High returns are a sure sign that the nutritive sub- 
stances of the soil are in a condition available to the 



EEASON OP IXCEEASE IN CEOPS. 



195 



roots ; the permanence of high returns, and that alone, 
affords a safe criterion of the total store or quantity of 
nutritive substances in the ground. 

The high returns yielded by one field above another 
result from this, that the particles of the mineral con- 
stituents lie nearer together in the one field than in the 
other : they depend upon the closeness of the nutritive 
substances. The following table may make this point 
clearer : — 

Cunnersdorf, Mausegast, Kotitz, Oberbobritzsch, Obersehona. 
Fig. I. 1851. Winter-eye. 




Fig. II. 1852. Potatoes. 



50 




M 















^ 




40 ^ 




^ 










^ 






m 


5 




io 




^ 


^ 





Fie HI. 1853. Oats. 



[ 


1 


^'■■~'~~~~--^ 








=. 




1 


t 


° ^~~"~~~~^ 1 ~~— .^ 


,. — -^ — ^ . 


h 


:= 




1 


"p 




^^■. — -^^ 




— - — 


e 


= 






1 










i^ 





196 



THE SYSTEM OP FAEM-YARD MANURING. 



Fig. IV. 1854. Cloveb. 



90 




1= 


k 


"^ 






k 




1 




80 




M 


=1 




VO 






=1 
=1 




bO 


=1 




bO 






g 




40 


- 


1 


=1 

m 




30 


m 




ao 






i 








10 




1 


m 


. 



In Fig. I., the perpendicular lines a b represent the 
produce of grain, a c that of straw ; in Fig. II., the lines 
de the produce of potatoes ; in Fig. III., the lines f g the 
produce of oat-corn, the lines fli that of oat-straw ; in 
Fig. IV., the lines i k the produce of clover, on the un- 
manured plots of ground on which the experiments were 
made in Saxony. 

Now if we assume that the roots of the rye and of the 
other plants, on the several fields, were of the same 
length and condition, it is quite certain that the roots of 
the cereals on the field at Mausegast found, in their way 
downwards, much more nutriment than those in the 
Cunnersdorf field : the corn line is twice as hioh, and 
the straw line one-third higher, in the former than in the 
latter. 

With an equal number of plants, and an equ.al length 
of root, certain nutritive substances required by corn 
were twice as close in the Mausegast as in the Cunners- 
dorf field. The hue in Fig. IV. representing the produce 
of clover is ten times as high for Cunnersdorf as for 



NEARNESS OF ELEMENTS OP FOOD IN SOILS. 197 

Oberbobritzsch, which means that the nutritive sub- 
stances required by clover were ten times as far asunder 
in Oberbobritzsch as in Cunnersdorf. 

In comparing the produce of several fields, the close- 
ness of the nutritive substances in the soil is in in- 
verse proportion to the height of the lines in the table 
indicatuag the amount of produce. 

The longer the lines, the closer are the nutritive sub- 
stances in the various soils ; the shorter the lines, the 
more widely asunder do the substances lie. 

For instance, the lines indicating the produce of pota- 
toes at Kotitz and Oberbobritzsch are as 18 to 9 ; the 
potato crop at Kotitz was twice as high as that at Ober- 
bobritzsch. Hence it follows that the distance between 
the nutritive substances was in inverse ratio, that is, as 
9 to 18 ; in the field at Kotitz they were twice as close 
together as in the other. 

This mode of viewing the matter is calculated to lead, 
in many cases, to more definite ideas respecting the cause 
of the exhaustion of a field. 

The corn and potato crops, for instance, took away 
phosphoric acid and nitrogen from the arable surface soil 
at Mausegast, and the barley plant next in rotation, 
which hkewise draws its nutriment from the surface soil, 
found in the third year much less nutriment than the rye 
plant which had preceded it. 

The elevations of the hues a b (Fig. I.) and/^^ (Fig. III.), 
taken inversely, show how much relatively greater 
has become the distance between the particles of the 
nutritive substances for the barley plant. The barley- 
corn requires for its formation the same nutritive sub- 
stances as the rye-corn. Now, as the produce of the 
rye-corn was to that of the barley-corn in the proportion 
of 22 : 12, this means, taken inversely, that the distance 



198 THE SYSTEM OF PAEM-YAED MANUEING. 

between the nutritive substances for the barley-corn had 
increased from 12 to 22. 

In the third year, the roots of the barley, for the same 
length, found scarcely half as much nutriment for grain 
as the rye had found. 

This exposition is not intended to supply a standard 
for measuring the distances between the available parti- 
cles of nutritive substances in the ground, but merely to 
define more accurately what is meant by the exhaus- 
tion of land. The farmer who has a clear view of the 
causes upon which depend the reduction of crops by con- 
tinuous cultivation, will thereby the more easily find out 
and apply the means to make his field as productive as 
before, and, if possible, even to increase its fertility. 

Beside the general differences of all the crops in the 
Saxon experiments, we are further struck with the 
inequahty in the proportion of corn and straw. 

To 10 parts by weight of corn, the yield of straw was 
respectively — at Cunnersdorf 25 parts by weight, at 
Kotitz 23, at Oberschona only 21, and at Mausegast 
only 20. 

A more careful examination of the table shows that 
the difference is mainly in the produce of corn. 

The fields at 

Cunnersdorf Kotitz Oberbobritzsch 

yielded in straw . 2951 lbs. 3013 lbs. 3015 lbs. 

that is, within a few pounds, the same quantity of straiv, 
while the amount of coim was in 

Cunnersdorf Kotitz Oberbobritzsch 

11 : 12 : 14 

In investigating the reasons for this inequality in the 
produce of corn, we discover at the same time the causes 
of the difference in the proportion betAveen the corn and 
straw. 

It is necessary to remember that what is called straw 



FORMATION OF STEAW. 199 

(i. e. the leaves, stalks, and roots) is formed from the 
albumen of the cereal seeds, that is, from the constituent 
elements of the seeds ; and, further, that these parts of 
the plant are the organs for the reproduction of these 
same seed constituents. 

The production of the straw always precedes the for- 
mation of the grain ; and that portion of the seed ele- 
ments which serves to form the organs of the plant can- 
not be used to make seed : or, the more seed-constituents 
are turned into straw-constituents within the appointed 
time of growth, the fewer will remain at the close of that 
period for the formation of seed (see p. 51). 

Before the period of flowering, all the seed-constituents 
go to form straw ; after that period, a division takes place. 

Therefore, if all other conditions of soil and weather 
are equally favourable, the quantity of straw will depend 
upon the amount of seed-constituents needed for the 
formation of straw. 

The quantity of corn depends upon the residue of seed- 
constituents in the whole plant, which are no longer 
required for the multiphcation and enlargement of leaves, 
stalks, and roots. 

Let K represent that portion of the corn-constituents 
that may be formed into seed ; dK the other fraction of 
the same substances, which remain as constituents in the 
straw ; and St the other constituents comprised in the 
straw : so that 

K=(pliosplioric acid, nitrogen, potash, lime, magnesia, iron) 
aK—a fraction of K 
Sf=(silicic acid, potash, lime, magnesia, iron) 

then the nutritive substances which the plant has absorbed 
from the soil, may be thus expressed : — 

(K + aK S^). 



200 THE SYSTEM OF FAEM-YARD MANUEING. 

This expression, therefore, means that the roots of the 
cereal plant must have absorbed from the earthy particles 
in contact with them a certain proportion of nutritive 
substances for the production of leaves, roots, and stalks, 
and after this an additional amount of several of the 
same constituents for the formation of grain. The total 
produce is, of course, dependent upon the sum of the K 
and S^ constituents, which the soil is able to supply to the 
plants during the natural period of growth. 

The ratio between corn and straw results from a divi- 
sion of the K and S^ constituents in the plant itself, and 
depends upon the relative proportion of the K and S^ 
constituents in the soil, as also upon the action of external 
causes favouring the production of corn or straw. 

When the quantity of K constituents in the ground 
decreases, less grain will be produced ; but it is only in 
certain cases that this will exercise any influence upon the 
produce of straw. 

Wlien the quantity of 3t constituents in a field is 
increased, the enhanced conditions for the formation of 
leaves, stalks, and roots, must injure the crop of grain, if 
the amount of oK required for the additional formation 
of straw is taken from the store of K contained in the 
soil. 

If one of two fields is poorer in K but richer in S;^ con- 
stituents than the other, the former may give the same, 
perhaps even a larger, amount of straw, than the latter, 
but its produce of corn will necessarily be less. 

A similar increase of straw, at the expense of grain, 
takes place when the state of the weather is more favour- 
able for the formation of leaves, stalks, and roots, than 
for grain. The period of growtli is thus prolonged, and 
the plant then takes up more of the St constituents, Avhich 
are usually in excess ; for the assimilation of these, a 



COEN AND STEAW CONSTITUENTS IN SOILS. 201 

certain additional quantity of the K constituents is con- 
sumed, which would otherwise have served to form seed. 
Let st represent the additional supply of S^ constituents 
afforded by the soil under these circumstances, and ah the 
additional portion of K converted into straw-consti- 
tuents ; then the alteration in the produce may be 
expressed as follows : — 

Com Straw 

(JL—ak) -f (aK ^t-\-alc st) 

that is, the produce of straw increases, while that of grain 
diminishes. It is also evident, that where the S^ consti- 
tuents are in excess and the amount of K constituents is 
increased, then if K is proportionately deficient there will 
be an increase in the produce of straw, and if K is pro- 
portionately increased there will be a larger produce both 
of corn and straw. 

As the constituents of K, with the exception of ni- 
trogen and phosphoric acid, are also constituents of S^, 
this accession of produce in the field under consideration 
will be also effected either by a supply of phosphoric 
acid, or of nitrogen, or both together. 

If by this supply the closeness of the K particles in 
the ground, or of the phosphoric acid and ammonia 
particles, is doubled, then under the most favourable 
circumstances the harvest may be doubled by the supply 
ofK. 

If, on the other hand, the soil is deficient in S^ consti- 
tuents, any increase of nitrogen or phosphoric acid in the 
ground will fail to exercise the slightest influence upon 
the crop. 

It results from this, as a matter of course, that the 
absolute or relative amount of straw, given by a field in 
a crop of corn, will furnish no proof of the Sf consti- 
tuents in the soil : since, though two fields may be equally 



202 THE SYSTEM OP FARM- YARD MANURING. 

rich in these constituents, the produce of straw depends 
upon the quantity of K constituents in the ground: 
hence the field which is richer in K, will, under like cir- 
cumstances, give a larger crop of straw. 

The fact, therefore, that the fields at Cunnersdorf and 
Oberbobritzsch yielded a like amount of straw, cannot 
lead to the inference that these fields contained an equal 
quantity of St constituents, since the corn crops show that 
the quantities of K were unequal. The harvests exhi- 
bited the folloAving proportions : — 

In Cunnersdorf as . . . (11) K : (29) aK St 
„ Kotitz as . . . . (12) K : (30) aK St 
„ Oberbobritzsch as . . (14) K : (30) aK St 

As before remarked, the constituents represented by 
the symbols K and St differ merely in this, that K com- 
prises nitrogen and phosphoric acid, while the other con- 
stituents of K are common to both ; hence the difference 
in the corn crops of these three fields results mainly from 
the fact, that the roots of the corn found in the soil at 
Kotitz -Jy and at Oberbobritzsch -f-j more phosphoric 
acid and nitrogen in an available condition than at 
Cunnersdorf. 

If the question is asked, how much phosphoric acid 
and nitrogen must be added to the field at Cunnersdorf in 
order to make the crop of corn equal to that of Ober- 
bobritzsch, it would be a mistake to suppose that an 
increase of -^y would be sufficient ; for the augmenta- 
tion of the produce of corn is materially influenced by 
the St constituents, the quantity of which varies greatly 
in different soils and has not been ascertained. 

By the addition of nitrogen and phosphoric acid, a 
certain quantity of the accumulated St constituents are 
rendered effective or available, which before Avere not so; 
but while the produce of straAv increases, not -^^y, 



RELATIVE PEOPORTIOISr OF COEN AND STEAW. 203 

but less of nitrogen and phosphoric acid remain over 
for the formation of seed ; the exact quantity is hmited 
by the total amount of transformed S^ constituents. 

The closeness of the St constituents in different soils 
may, however, be approximately ascertained from the 
relative proportion of corn and straw obtained from a 
plot manured with phosphoric acid and nitrogen, and 
from an unmanured plot respectively. 

If the unmanured plot yields corn and straw in the 
proportion of 1:2-5, and the manured plot gives a larger 
crop in which the corn is to the straw as 1 : 4 (straw 
being in greater proportion), it is evident that the St 
constituents preponderate in the latter field ; and a much 
larger quantity of phosphoric acid and nitrogen would 
have to be supphed in order that the field, correspondent^ 
with its amount of St constituents, might produce the same 
relative proportion of corn and straw as, for example, the 
land at Oberbobritzsch. 

It is a very essential part of the farmer's business to 
study the nature of his field, and to discover which of the 
nutritive substances, useful to plants, his land contains in 
preponderating quantity : for thus he will know how to 
make a right selection of such plants as require for their 
developement a superabundance of these constituents ; and 
he will obtain the greatest profit from his field, when he 
knows what nutritive substances he must supply in due 
proportion to those which are already in abundance. 

Two fields, in which the total amount of nutriment is 
unequal, but the relative distribution of the substances is 
the same, will produce crops differing in quantity, but 
agreeing in the relative proportion between corn and 
straw. 

Such a relation, for example, exists between the field 
at Oberbobritzsch and tlie field at Mausegast. If the crop 



204 



THE SYSTEM OF FAEM-YAED MANUEING. 



of corn and straw in tlie former is expressed by K-|- oK S^, 
the crop in the latter =lJK-fl J (2K S^. 

The fields are evidently cultivated in both places with 
great care and skill, and the soil is so uniformly mixed, 
that when we know the corn and straw crop of the one, 
and the straw crop of the other, we can calculate the corn 
crop of the latter from the above formula. 

Potatoes, 1852. — In the subjoined table, the vertical 
lines show the potato crops from the five different fields in 
the year 1852. 

1852. Potatoes. 
Cunnersdorf, Maiisegast, Kotitz, Oberbobritzsch, Obersehona. 




The potato plant draws its principal constituents from 
the arable surface soil, and from a somewhat deeper layer 
than the rye plant ; and the crops reaped show the 
condition of the layers more accurately than could be 
ascertained by chemical analysis. 

In the fields at Mausegast and Cunnersdorf the nutritive 
substances available for the potato plant Avere about 
equally close ; in Kotitz tliey were one-ninth closer to each 
other ; at Oberbobritzsch they were twice as far asunder ; 
while at Obersehona they were one-fifth closer than in 
Oberbobritzsch. 

The largest potato crop was obtained from the field at 
Kotitz. Potash (for the tubers) and lime (for the herb- 
aceous parts) are the predominant constituents of the 
potato plant : but a certain amount of nitrogen and phos- 



A POTATO-CEOP AND THE MINEEALS IN THE SOIL. 205 

plioric acid is as necessary for the developement of the 
potato as it is for cereals ; and the effective quantity 
of the transmuted potash and hme is essentially determined 
by the phosphoric acid and nitrogen absorbed at the same 
time. Where one of the two latter elements which, as 
we have remarked, are equally constituents of cereals, 
is deficient in the soil, the potato crop will be propor- 
tionate to the available quantity of these two substances, 
and the greatest excess of potash or lime in the soil will 
have no influence whatever upon the amount of the 
produce. 

The arable surface soil of the field at Oberbobritzsch is 
much richer in phosphoric acid and nitrogen than that of 
the Kotitz field ; yet the potato crop 3delded by the former 
was only half that given by the latter. 

Accordingly, nothing can be more certain than that the 
field at Oberbobritzsch contained much less potash or 
lime in an available state, than the Kotitz field ; and by 
manuring with lime alone, or with wood-ashes (potash 
and lime), it might readily be ascertained in which of the 
two substances the ground was deficient. 

But from the inferior potato crop given by the field at 
Cunnersdorf, we cannot infer that it was poorer in potash 
or lime than the field at Kotitz ; the latter decidedly con- 
tained, as the preceding corn crop shows, somewhat more 
phosphoric acid and nitrogen than the field at Cunners- 
dorf : consequently, the larger potato crop at Kotitz may 
have been mainly owing to the greater quantity of these 
two elements contained in it. Even if the field at Cun- 
nersdorf had been still richer in potash and lime than 
the Kotitz field, yet after all, under the given conditions, 
it would have produced a smaller crop of potatoes. 

Oats,lSbS. — The oat plant derives part of its nutriment 
from the arable surface soil, but sends its roots, when the 



206 



THE SYSTEM OP FAEM-YAKD MANUEING. 



soil permits, much deeper than the potato ; it possesses, 
so to speak, a higher power of vegetation than the rye 
plant, and in the faculty of appropriating nutriment re- 
sembles weeds. 

1853. Oats. 
Cunnersdorf, Mausegast, Kotitz, Oberbobritzsch, Oberschona. 




The point which most strikes us in this table is the 
great inequality in the produce of two cereal plants 
grown successively on the same unmanured soil. 

The field at Cunnersdorf, which next to that at Ober- 
schona had given the lowest crop of rye-corn and straw, 
yielded in the third year the largest produce of oat-corn 
and straw. 

The difference in the condition and closeness of the 
nutritive substances in the lower layers of these fields is 
undeniable. The field at Cunnersdorf was poorer in the 
upper layers, but went on increasing downwards in the 
amount of substances nutritive to the corn plant ; the 
other fields decreased downwards. 

The returns of the field at Mausegast for the year 1853 
refer to barley and not to oats : hence they afford no 
conclusion as to the condition of the deeper layers, from 
which the oat plant derives its food : but they show the 
state into which the arable surface soil had been brought 
by the preceding corn crop. Owing to the abstraction 
of phosphoric acid, and perhaps of nitrogen, the yield 
of barley-corn was much less than might have been 
expected from the soil, judging by the preceding rye 
crop ; and a small supply of superphosphate or guano 



CLOVER CEOPS AND THE MINEEALS IN THE SOIL. 207 

would have greatly increased the produce of barley on 
this field. 

Clover, 1854. — The clover crops in the fourth year 
afford an insight into the condition of the deepest layers 
from which plants draw their food. 

1854. Clover. 
Cuunersdori, Mausegast, Kotitz, Oberbobritzsch, Obersebona. 



90 




1 


k 








k 




=1 
^1 




SO 






gl 

ii 
=1 


- 


TO 
60 




1 


bO 


ii 


- 


80 




M 




I 


=1 

=1 




10 


1 


— 






W 



The produce of clover at Cunnersdorf was nearly twice 
as large as at Mausegast, and ten times greater than at 
Oberbobritzsch ; and it is beyond doubt, that these un- 
equal crops must have corresponded to unequal amounts 
in the soil of substances nutritive to the clover plant. 

The substances required by the clover plant, in respect 
of quantity and relative proportion, are very nearly the 
same as for the potato plant (leaves, stalks, and tubers 
included) : and if clover still 5delds good crops upon a soil 
wherein potatoes thrive but imperfectly, this is chiefly 
owing to the wider root-ramification of the clover plant. 
There are scarcely any two other plants which so clearly 
indicate the layers of the soil assigned to them by nature, 
for the absorption of their nutriment. 

If potatoes are planted in trenches two feet deep, and 



208 



THE SYSTEM OP FARM-TAED MANUEING. 



if these are filled up in proportion as the plant grows, so 
that at last the earth in the trench is on the same level 
with the arable surface, it is always found that the tubers 
are formed only in the topmost layer, none at a greater 
depth, and not more in number than if the seed-potatoes 
had been planted only 1-^ or 2 inches deep in the arable 
surface soil : and on gathering the crop it is observed 
that the roots below the arable surface have died away. 

With clover, the case is reversed ; and although the 
arable surface soil at Kotitz, for example, is decidedly 
richer in substances nutritive for clover than that in 
Cunnersdorf (yielding a potato crop higher by one- 
eighth), this had no effect upon the clover, which receives 
its principal nutriment from the deepest layers of the soil. 

We now proceed to an analysis of the returns which 
were obtained, in the Saxon experiments, by employing 
farm-yard manure upon the plots of the same fields, the 
crops of which in their unmanured state we have just 
been considering. 



Produce^ per Saxon acre, of tlie fields dressed with farm-yard manure. 





Cunnersdorf 


Mauseg'ast 


Kotitz 


Oberbobritzscli 


Oberscbona 


Farm-yard 
manure 


cwt. 
180 


cwt. 
194 


cwt. 
229 


cwt. 
314 


c^^'t. 
897 


1851 

Rye corn , 

,, straw . 


lbs. 
1513 
4696 


lbs. 
2583 
5318 


lbs. 
1616 
4019 


lbs. 
1905 
3928 


lbs. 
1875 
3818 


1852 
Potatoes . 


17946 


20258 


20678 


11936 


16727" 


1853 

Oat corn . 
„ straw 


2278 
2992 


1649 

2475 


1880 
1742 


1685 
1909 


1253 
2576 


1854 
Clover-hay 


9509 


7198 


1232 


2735 


0* 



* The clover crop failed from excessive wet. 



THE PRODUCE NOT IN PEOPORTION TO THE MANURE. 209 



Increase hy farm-yard manure over unmanured plots. (See p. 190.) 





Cunnersdorf 


Mausegast 


Kbtitz 


Oberbobritzsch 


Oberschbna 


1851 
Rye corn 
„ straw 


lbs. 

337 
1745 


lbs. 

345 
736 


lbs. 

352 
1006 


lbs. 

452 
915 


lbs. 

1167 
229 


1852 

Potatoes 


1279 


3362 


2101 


2185 


5632 


1853 
Oat corn 
,, straw 


369 
429 


360 
635 


541 
385 


157 

97 


171 
862 


1854 
Clover-hay 


365 


1615 


137 


1824 


* 



Here, again, what strikes us first is tliat the returns 
from all the fields were clifTerent fr^om one another, and 
that apparently they did not bear the most remote rela- 
tion to the quantity of manure applied. 

Nothing can be more certain than the fact that a field, 
exhausted by cultivation, will yield larger returns if 
dressed with farm-yard manure than if unmanured : now, 
taking the increase to be caused by manure, it is natural 
to suppose that the same quantity of manure would pro- 
duce the same increase upon different fields. The follow- 
ing table, however, shows that the same quantity of 
manure, upon the Saxon fields, produced results which 
differed very considerably. 

One hundred cwt. of farm-yard manure gave increased produce. 





Ctmnersdorf 


Mausegast 


Kotitz 


Oberbobritzscb 


Obersclibna 




lbs. 


lbs. 


lbs. 


lbs. 


lbs. 


1851-53 












Winter rye 












and oats 


1539 


1070 


988 


515 


501 


1852 












Potatoes . 


720 


1723 


917 


696 


628 


1854 












Clover 


203 


832 


60 


628 


— 



The clover crop failed from excessive wet. 
P 



210 THE SYSTEM OP FAEM-YAED MAJ!^UEING. 

No one looking at these numbers could divine that 
they were intended to represent the effects produced upon 
five different fields by an equal quantity of the same 
manure, and that too the universal manuring agent. 

Neither in the crop of rye-corn and straw, nor in that 
of potatoes, oats, and clover, is there the shghtest re- 
semblance or correspondence ; still less is it possible to 
discover what amount of maniure has been instrumental 
in producing the increased crops. 

The same quantity of farm-yard manure gave, in the 
years 1851 and 1853, at Mausegast double, at Cunnersdorf 
three times, the increase of cereal crops, corn and straw 
together, that was obtained atOberbobritzsch : the increase 
of the potato crop at Mausegast was twice as large as in 
Kotitz ; of clover, four times more in Mausegast than in 
Cunnersdorf; and in Oberbobritzsch, ten times as much 
as m Kotitz. 

The enormous quantity of farm-yard manure put upon 
the field at Oberschona failed to produce anything hke 
the crop obtained from the unmanured field at Mause- 
gast. 

The composition of farm-yard manure, as we know 
from numerous analyses, is on the whole so much alike 
in all places, that we may suppose without great risk of 
error that in 100 cwt. of farm-yard manure every field 
receives the same nutritive substances and in the same 
quantities. 

The constituents of farm-yard manure act everywhere 
in the same way upon the soil or the earthy particles. 
Now this apparently involves an irreconcilable contra- 
diction with the fact that the increase obtained by it is 
nevertheless everywhere different, and that the dung- 
constituents supplied will, on one field, set in motion and 
render available to the cereal or potato .plants growing on 



CROPS FROM FARM-YARD MANURE VARY. 



211 



it, twice or three times as many elements of food as on 
another field. 

This fact does not refer to the Saxon fields alone, but 
applies generally. Nowhere, in no country, do the crops 
obtained by farm-yard manuring on different fields ever 
correspond, as the following table of the average produce 
of divers crops in different provinces of the kingdom of 
Bavaria will show. 

Average Crops in Bavaria. 

(Seufferfs Statistics.) 
One day's work yields average produce in bushels.* 



Upper Bavaria . 


Wheat 


Eye 


Spelt 


Barley 


Oats 


1-70 


1-80 


3-40 


1-90 


2-31 


Lower Bavaria . 


2-50 


1-80 


3-40 


1-90 


2-31 


Upper Palatinate and Eatis- 












bon .... 


1-45 


1-40 


2-70 


1-75 


1-85 


Upper Franconia 


1-20 


1-30 


2-20 


1-30 


1-75 


Middle Franconia 


1-65 


1-40 


3-50 


1-65 


2-25 


Lower Franconia and Ashaf- 












fenburg .... 


1-70 


1-75 


2-50 


2-00 


2-75 


Suabia and Neubiirg . 


1-80 


2-00 


5-0 


2-30 


3-50 


Palatinate .... 


2-70 


2-60 


4-80 


3-75 


3-90 



The crops produced by farm-yard manuring differ not 
only in every country, but even in every locality ; and, 
strictly speaking, every field dressed with farm-yard 
manure yields an average produce of its own. 

The action of farm-yard manure upon the increase of 



* 1 Hectolitre weighs 


on an average 


1 Bavarian bushel. 




ZoUverein weight 


ZoLLverein weight 


Wheat .... 


. 146 lbs. 


330—345 lbs. 


Barley .... 


. 128 „ 


290—300 „ 


Eye ... . 


. 140 „ 


318 325 „ 


Oats .... 


. 88 „ 


200—300 „ 


Spelt (in the husk) 


• 79 „ 


174 220 „ 



According to this scale, the weight of a Prussian bushel of wheat is 
83 lbs., and that of the EngHsh quarter 425 lbs., 100 lbs. (Zollv. weight 
= 110-2 lbs. avoir.). 

p 2 



212 THE SYSTEM OP FAEM-YAED MANUKING. 

produce is intimately connected with the condition and 
composition of the soil ; it varies, therefore, in different 
fields, simply because the composition of the soil varies. 

To understand the action of farm-yard manure, it is 
necessary to remember that the exhaustion of a field 
arises from the loss of a certain amount of nutritive con- 
stituents, at the end of a rotation, inflicted upon the soil 
by preceding crops, which of course leave less available 
food in the soil for the following crops. 

However, the loss of each individual constituent has 
not the same effect upon the exhaustion of the soil. 

The loss of hme which a calcareous soil suffers by a 
cereal or by clover, matters little to the growth of a suc- 
ceeding plant that requires large quantities of lime to 
thrive well. The same applies equally to the loss of potash, 
magnesia, iron, phosphoric acid, nitrogen, on fields seve- 
rally abounding in potash, magnesia, iron, phosphoric 
acid, or ammonia. Where a soil is abundantly provided 
with one of the mineral constituents, the amount of that 
constituent removed by the crops is so small a fraction of 
the whole mass, that the effect of the diminished store is 
not appreciable from one rotation to another. 

But practical experience shows that the crops do 
decrease from one rotation to another, and that the land 
requires a fresh supply of certain ingredients by manur- 
ing, if it is again to produce as large harvests as before. 

Now, as a supply of lime cannot be expected to 
restore the fertility of an exhausted field where lime con- 
stitutes the principal bulk of the soil, just as little as a 
supply of potash or phosphoric acid to a field abounding 
in potash or phosphoric acid, it is easy to understand that 
where the productive power of an exhausted field is 
restored, the fertihsing effect is to be attributed simply to 
the manure returning to the field those elements of food 



CROPS, HOW GOVERNED. 213 

which the soil originally contained in the least propor- 
tion, and of which it has accordingly lost, by the pre- 
ceding crops, comparatively the largest fraction. 

Every field contains a maximum of one or several, and 
a minimum of one or several, other nutritive substances. 
It is by the minimum that the crops are governed, be it 
lime, potash, nitrogen, phosphoric acid, magnesia, or any 
other mineral constituent ; it regulates and determines 
the amount or continuance of the crops. 

Where lime or magnesia, for instance, is the minimum 
constituent, the produce of corn and straw, turnips, pota- 
toes, or clover, will not be increased by a supply of even 
a hundred times the actual store of potash, phosphoric 
acid, sihcic acid, &c., in the ground. But a simple dress- 
ing with hme will increase the crops on a field of the 
kind, and a much larger produce of cereals, turnips, and 
clover will be obtained by the use of this agent (just as 
is the case by the application of wood-ashes on a field 
deficient in potash) than by the most liberal use of farm- 
yard manure. 

This sufficiently explains the dissimilar action upon 
different fields of so composite a manure as farm-yard 
dung. 

Only those ingredients of farm-yard manure which 
serve to supply an existing deficiency of one or two of 
the mineral constituents in the soil act favourably in 
restoring the original fertility to a field exhausted by 
cultivation ; all the other ingredients of the manure, 
which the field contains in abundance, are completely 
without effect. 

A field rich in straw-constituents cannot be made more 
productive by manuring with straw-constituents in the 
dung, whereas these constituents will prove most effi- 
cacious on fields deficient in them. 



214 THE SYSTEM OF PAEM-YAED MANUEING. 

If two fields have the same abundance of straw-con- 
stituents, but are not equally rich in corn-constituents, 
the same supply of farm-yard manure will not produce, 
by any means, equal crops of corn, because these must 
bear a relation to the corn-constituents supphed in the 
manure. Of these, both fields received the same amount 
in the same quantity of manure ; but as the one field, of 
itself, was richer in corn-constituents than the other, the 
poorer of the two must receive much more manure to 
make it produce as large crops as the other. 

A comparatively small quantity of superphosphate 
will, on a field of the kind, serve to increase the produce 
to a much greater extent, than the most liberal use of 
farm-yard manure. 

Upon a field deficient in potash farm-yard manure acts 
by the potash contained in it ; upon a soil poor in mag- 
nesia or lime, by its magnesia or lime ; upon one poor in 
sihcic acid, by the straw in it ; upon land poor in chlo- 
rine or iron, by the chloride of sodium, chloride of potas- 
sium, or iron contained therein. 

This fact accounts for the high favour in which farm- 
yard manure is held by practical farmers. As the dung 
of the farm-yard contains, under all circumstances, a cer- 
tain quantity of each of the mineral constituents with- 
drawn from the soil by the crops grown on it, its action 
is universally beneficial. It never fails to produce the 
desired effect, and thus spares the practical man the 
trouble of devising more suitable and equally efficacious 
means for keeping up the fertility of his fields, with a less 
profuse expenditure of money and labour, or of raising 
his land, without additional outlay, to the highest attain- 
able degree of fertihty compatible with its composition. 

It is Avell-known in practice, that the produce of many 
fields may be increased by manuring with guano, bone- 



EREOE IN USING TOO MUCH MANURE. 215 

dust, rape-cake, and other substances containing only cer- 
tain constituents of farm-yard manure ; and their opera- 
tion is explained, in effect, by the doctrine of minimum, 
which I have just laid down. 

But as the practical farmer is not acquainted with 
the law which regulates the operation of these manuring 
agents as affecting the increase of produce, he can, of 
course, have no correct notion of their rational, which 
means their truly economical, use ; he puts on his land too 
much, or too little, or chooses the ^vrong agent. The 
error of employing too httle manure needs no expla- 
nation ; for every one knows that the right proportion of 
manure will, with exactly the same labour and at a 
trifling additional outlay, ensure the maximum produce of 
which the land is capable. 

The error of using too much manure arises from the 
mistaken notion that the action of manures is propor- 
tionate to the quantities in which they are applied ; this 
is true up to a certain limit, but beyond this all the 
manure applied is simply thrown away, as far as any fer- 
tilising action is concerned. 

A manuring experiment made by Mr. J. Eussell, of 
Craigie House (' Journal of the Eoyal Agr. Soc. of Eng- 
land,' vol. xxii. p. 86), may, perhaps, serve to illustrate 
our meaning. In this experiment a field was divided 
into a number of plots of three rows each, all planted 
with turnips, some of the plots being left unmanured, the 
remainder dressed severally with different manuring 
agents, among others with superphosphate (bone-ash 
dissolved in sulphuric acid). The produce, calculated 
per acre, was as follows : — 



216 THE SYSTEM OF FAKM-YARD MANURlM. 







Produce per 


acre. 




No. of plots 












Cwt. 


I. Unmanured 




. 






. 


340 ttirnips (Swedes) 


II. „ 










. 


320 


V. Manured with 5 cwt 


. of 


sup 


erphc 


)spliate 


535 


VI. 


5 „ 






)7 




497 


VII. 


3 „ 






)) 


• 


480 


VIII. 


7 „ 






7J 




499 


IX. 


10 „ 






)) 


. 


490 „ 



As shown by the difference of 20 cwt. in the produce 
of the unmanured plots, the condition of the soil and 
the store of mineral constituents differed, to some extent, 
in different parts of the field. Other experiments, which 
we cannot describe more particularly, showed that the 
soil was poorer in the centre of the field than on the 
sides. 

The one great fact most clearly proved by the above 
table of produce is, that 3 cwt. of superphosphate gave 
nearly the same crop of turnips as 5 cwt. ; and that a 
further increase of the manure to 10 cwt. produced no 
additional increase of the crop. 

No steps were taken, in these experiments, to ascertain 
which of the constituents of superphosphate of lime had 
the principal share in increasing the produce of the field. 
Magnesia and lime, as well as sulphuric and phosphoric 
acid, are equally indispensable elements of food for the 
turnip plant; and I have observed that by manuring 
with gypsum and a httle common salt or with phosphate 
of magnesia, a field wih be made to give more abundant 
crops than by employing superphosphate of lime, although 
the latter unquestionably proves the most effective ma- 
nure for most fields. 

To apprehend these facts correctly, we must remember 
that the law of the minimum does not apply to one con- 
stituent alone, but to all. Where, in any given case, the 
crops of any plant are limited by a minimum of phos- 



THE LAW OP MINIMUM. 217 

plioric acid in tlie field, tliese crops will increase by 
augmenting the quantity of phosphoric acid up to the 
point at which the additional phosphoric acid bears a 
proper proportion to the next minimum constituent in 
the soil. 

If the additional phosphoric acid exceeds the corres- 
ponding quantity, for instance, of potash or ammonia in 
the soil, the excess will prove of no effect. Before the 
supply of phosphoric acid, the available quantity of 
potash or ammonia was a little larger than the amount 
of phosphoric acid in the soil, and the excess of the 
alkalies was ineffective until the phosphoric acid was sup- 
plied ; similarly the excess of phosphoric acid must 
remain just as inoperative, as previously the excess of 
potash. 

Whilst the produce before was proportionate to the 
minimum of phosphoric acid, it is now in proportion to 
the minimum of j)otash or ammonia, or both alkahes. A 
few experiments made on Mr. Eussell's field might have 
settled the question. Had potash or ammonia been the 
minimum, after manuring with superphosphate, a suitable 
supply of potash or ammonia, or both, would have 
increased the produce. In this same series of experi- 
ments, 6 cwt. of guano, corresponding to 2 cwt. of super- 
phosphate, gave a crop of 630 cwt. of turnips, or 130 cwt. 
more than the superphosphate ; but it is left in doubt 
whether this increase was attributable to the potash or 
the ammonia in the guano. 

To return to our Saxon experiments. If we look at 
the different quantities of dung applied severally on the 
five fields, we are naturally led to inquire the reason of 
this diversity. 

The most feasible answer, perhaps, is, that the farmer 
gives as much manure as he has at his disposal, or that 



218 THE SYSTEM OP FARM-YAKD MANUEING. 

he regulates the quantity according to certain facts. If 
he has found by experience that a certain quantity of 
farm-yard manure will restore his land to its original 
fertility, and that more copious manuring will fail to give 
larger crops, in proportion to the additional supply, or to 
the cost incurred in collecting the manure, he will stop at 
the smaller quantity. 

Hence it cannot be regarded as a mere accident that the 
farmer at Cunnersdorf contented himself with 180 cwt. 
of farm-yard manure, while the farmer at Oberbobritzsch 
laid 314 cwt. upon his field. 

But if the quantity of manure to be applied is not 
dependent upon chance or caprice, but is regulated by 
the object in view, it is manifest that the proceedings of 
the farmer are governed by a law of nature unknown to 
him, except by its effects. 

It is in the composition and condition of the soil that 
we must seek the law which regulates the quantity of 
farm-yard manure required, at the outset of a fresh rota- 
tion, to restore a field to its former fertility ; and it is not 
difficult to see that this quantity must always be propor- 
tionate to the effective dung-constituents already present 
in the soil ; a field largely abounding in them takes less 
manure than a poor field to give the same increased 
produce. 

Now, as farm-yard manure owes its most active con- 
stituents to clover, turnips, and the grasses, the inference 
is pretty clear that the quantity of this manure required 
on a field is in an inverse ratio to the produce of clover, 
turnips, or grass, which the field can give when unma- 
nured. 

The Saxon experiments show that this inference cannot 
be far from the truth, in one respect at least ; for on 
comparing the produce of clover given by the unmanured 



AMOUNT OF FARM-YAED MANUEE REQUIEED. 219 

plots with the quantity of farm-yard manure applied, we 

find : — 

Clover crops in 1854. 

Cunnersdorf Mausegast Kbtitz Oberbobritzsch. Obersch'dna 

Pounds . 9144 5583 1095 911 _ 

Quantity of manure applied in 1851. 
Cwt. . 180 194 229 314 897 

The field at Cunnersdorf which contained the largest 
store of dung-constituents received the smallest ; the 
field at Oberbobritzsch which gave the smallest crop of 
clover, the largest quantity of farm-yard manure. 

The crop of clover, however, is not the only factor to 
determine the amount of farm-yard dung required for 
manuring ; for one of the clover-constituents, silicic acid, 
which is indispensable to the cereal plants, is present 
only in trifling proportion, and hence the quantity of 
farm-yard manure (straw-manure) must bear a definite 
ratio to the quantity of straw-constituents abeady present 
in the ground. 

If, in the Saxon experiments, we compare the increased 
produce of corn and straw obtained from the fields 
manured with farm-yard dung, we find : — 

Increase of produce hy farm-yard manuring, per acre. 

Cunnersclorf Kotitz Oberbobritzsch 

Quantity of farm-yard manure . 180 cwt. 229 cwt. 314 cwt. 

Corn 347 lbs. 352 lbs. 452 lbs. 

Straw 1743 „ 1006 „ 914 „ 

The field in Cunnersdorf, manifestly the richest in sub- 
stances nutritive for straw, gave the largest straw-crop, 
although it had received the smallest quantity of farm- 
yard manure. In the increased produce, corn was to 
straw as 1:5, clearly showing that sparing application 
of straw-manure was the proper course to pursue here. 
This fact readily explains also why the field at Ober- 



220 TPIE SYSTEM OF FARM-YARD MANURING. 

bobritzsch, comparatively poorer in straw-constituents, 
required 85 cwt. of farm-yard manure more than the 
Kotitz field, to enable it to maintain, in its increased pro- 
duce, the same proportion of corn and straw (1 : 2) as in 
the crop from the unmanured plot. 

These considerations might, perhaps, lead the practical 
farmer to the conviction that he is, after all, not much of 
a free agent in the cultivation of his fields, and that the 
' facts and circumstances ' which guide him in his pro- 
ceedings are simply laws of nature, of whose existence 
he has scarcely any conception. In truth, it may be said 
that the agriculturist is a free agent only in his wrong- 
doings. If he acts in accordance with his own interest, 
he must allow himself to be guided, even though uncon- 
sciously, by the condition of his land ; and the only 
matter for wonder is, how far the man of ' experience ' 
has succeeded in this way. 

A system of farming, to be called truly rational, must 
be exactly suited to the nature and condition of the soil ; 
for it is only when the rotation of crops or the mode 
of manuring is conformable to the composition of the 
soil, that the farmer has a sure prospect of realising the 
highest possible returns from his labour or from the 
capital invested. 

Now considering, for instance, the great difference in 
the condition of the soil at Cunnersdorf and Oberbobritzsch, 
it is self-evident that the same rotation of crops which suits 
the one field, will not answer equally well for the other. 

If farmers would only make up their minds to acquire 
by experiments on a small scale,* an accurate knowledge 
of the productive power of their land for certain kinds or 
classes of plants, a few more experiments would readily 

* In a field of pretty uniform composition, experiments of this kind 
may be made witli flower pots sunk in tlie earth. 



LIMITED VALUE OF CHEMICAL ANALYSIS. 221 

enable them to discover what nutritive substances their 
land contains in minimum proportion, and what manuring 
agents ought to be applied to ensure the production of a 
maximum crop. 

In matters of this kind the farmer must pursue his own 
course, and the proper course is the one that will most 
fully secure the object he has in view ; he must not put 
the least faith in the assertion of any foolish chemist, who 
wants to prove to him analytically that his field contains 
an inexhaustible store of this or that nutritive substance. 
For the fertility of a field is not proportionate to the 
quantity of one or several food elements analytically 
shown to exist in it, but to that fraction of the total 
nutritive substances which the field is able to give up to 
the plants ; and the only means of determining that 
fraction is by the plant itself. The most that chemical 
analysis can do is to supply a few data for comparing the 
condition of two fields. The experiments made by the 
beet-root growers on the extensive tract of land in Eussia, 
known as the Tschernosem or ' Black soil,' whose fertility 
for corn plants is proverbial, show that this earth, though 
analytically proved to contain upon the whole, to a depth 
of twenty inches, 700 to 1000 times the quantity of 
potash required for a full beet-root crop, is, after three or 
four years' cultivation, so exhausted, that without manur- 
ing it will no longer yield a remunerative crop of beetroot.* 

* With regard to the general opinion about the abundance and 
inexhaustibility of potash in land, the folloAving announcement, in the 
'■ Badische Centralblatt fur Staats und Gemeinde- Inter essen,' May 1861, 
is not without interest. ' In the District of Bretten. — The contracts 
which usually take place in the early part of the year for the cultivation 
of beetroot, are now fully ojDcn for competition in this district, and for 
good articles 30 francs the cwt. are offered this year, whereas last year 
only 26 francs were paid. Notwithstanding this rise of prices, and the 
premiums offered for superior roots, not many transactions have been 
concluded. The reason of this is qiiite intelligible, for the very injurioiis 



222 THE SYSTEM OF FARM-YARD MANURING. 

In the produce of cereals there is only one proper pro- 
portion between grain and straw ; but the unfavourable 
proportions are many. It is clear that the mass and 
extent of the organs for the formation of grain (in other 
words, the bulk of the straw) must bear a definite relation 
to the product, that is, to the quantity of grain produced : 
any excess or deficiency in the amount of straw must 
always act injuriously upon the grain crop. 

When it is known that, on a given field, one part by 
weight of corn to two parts by weight of straw is the 
most favourable proportion for the production of grain, 
then, according to theory, the manuring of the field should 
not be such as to cause any marked alteration of this 
relative proportion in the increased produce ; that is to 
say, the several manuring substances should be selected 
and laid upon the field in such quantity and relative pro- 
portion, that the composition of the soil may remain the 
same as it was before. 

It is well known that certain manuring substances are 
especially favourable to the formation of the herbaceous 
parts of plants, others to that of seed. Phosphates, as a 
general rule, increase the grain crop : whilst of gypsum 
it is well known that where that substance efiects an 
increase in the produce of clover-hay, this increase is 
always attended with a marked diminution in the produce 
of seed. The cultivation of potatoes or Jerusalem artichokes 
tends to reduce the excessive accumulation in the arable 
surface soil, of substances which promote the formation of 
the herbaceous parts of plants. Theoretically, therefore, 
it is not impossible to maintain a certain uniformity of 
composition in the soil of a field ; but this cannot be 

effects resulting to land on Avliich this product has been cultivated, are 
too well known.' The effects must have reference to fields which had 
been adequately manured, for otherwise no profitable returns can be 
expected. 



PERMEABILITY OF SOILS TO MANURES. 223 

effected by carrying on the liusbandry of an estate by 
the system of farm-yard manuring. It Avill hereafter be 
shown that by the continuous and exchisive use of farm- 
yard manure, the composition of the soil is found changed 
after each rotation. 

The last point which claims our attention, in reference 
to the Saxon experiments, is the difference in the per- 
meabihty of the soil to the dung-constituents in the 
different localities. The depth to which the alkalies, the 
ammonia, and the soluble phosphates penetrate, depends 
of course upon the absorptive power of the soil ; now, 
assuming, for the sake of illustration, the soil of a field to 
be divided from the top downwards into distinct layers, 
which are not of course sharply separated from one 
another, we find that in some localities the dung-con- 
stituents stop in the upper layers, whilst in others they 
penetrate to the deeper layers of the ground. Thus, 
for instance, in the Cunnersdorf field the clover crop had 
derived no benefit from the farm-yard manure, being about 
only 4 per cent, larger than the produce given by the 
unmanured plot ; whereas at Mausegast the manuring 
caused an increase of 30 per cent., and at Oberbobritzsch 
of 200 per cent. This result shows that certain mineral 
constituents, indispensable for clover, penetrated much 
deeper into the ground at Mausegast and Oberbobritzsch 
that at Cunnersdorf and Kotitz ; or, what comes to the 
same, that, in the two latter places, they were, on their 
way downwards, retained by the upper layer of the soil. 
On comparing the crops given by the unmanured plot at 
Cunnersdorf with those obtained from the unmanured 
plots in the other locahties, we see that the Cunnersdorf 
field contained nearly as large a store of straw constituents 
as the fields at Kotitz and Oberbobritzsch, while it was 
decidedly poorer in the principal grain constituents, 



224 THE SYSTEM OF FARM-YAED MAJSTUEING. 

namely in phosphoric acid and, perhaps, also in nitrogen. 
Hence, with an equal supply of phosphates and ammonia 
on the three fields, the topmost layer of the ground at 
Cunnersdorf, being poorer in these constituents, would 
retain a great deal more of them than that of the other 
two fields. 

The increase in the potato crop and in the produce of 
oat-gram and straw, on the Cunnersdorf field, clearly 
indicates that certain dung-constituents made their way 
to that layer of the soil from which the roots of the oat 
plant principally derive their food, which layer, being 
richer in corn and straw constituents than the arable 
surface soil, permitted a small proportion of nutritive 
substances to pass through it and thus reach the clover. 

If we compare with this the field at Kotitz, and look 
at its extraordinarily scanty crop of oat-grain and straw, 
we see at once that in the latter field the deeper layers of 
the soil were much poorer in corn and straw constituents, 
but that the topmost layer was much richer in corn 
constituents than the land at Cunnersdorf. 

Although the Kotitz field received above 25 per cent, 
more farm-yard manure than the Cunnersdorf field, yet 
only a very insignificant portion of that manure found its 
way down to the clover, as the layer above had retained 
the substances nutritive to clover, and these had prin- 
cipally served to benefit the oat-plant. The increase in 
the produce of oat-grain at Kotitz was more than double 
that obtained from the Cunnersdorf field. At Mausegast 
the relations were similar ; from the uncommon abundance 
of corn and straw constituents in the arable surface soil, 
the absorptive or retentive power of the latter for the 
dung-constituents in solution was comparatively less, 
and a considerable proportion of these substances was 
thus permitted to reach the deepest layers. The uniform 



OBSERVATION AND REFLECTION IN AGRICULTURE. 225 

rise of the successive crops obtained from the manured 
field at Oberbobritzsch evidently shows a very uniform 
distribution of active dung-constituents, such as might be 
expected in a soil which, though not exactly sandy, yet 
contained a larger proportion of sand than any of the 
other experimental fields. 

It is easy to see, that by knowing the absorptive power 
of the arable soil in these several fields, the farmer is 
enabled to determine beforehand to what depth the nutri- 
tive substances supplied in the manure will penetrate into 
the ground ; and it follows, as a matter of course, that he 
is able to apply with greater effect the mechanical means 
at his disposal for promoting the distribution of these 
elements in the soil, in the right places and in the proper 
manner. 

It would answer no good purpose to expatiate still fur- 
ther on this point; my object has been to chrect the 
attention of the farmer to the different facts or pheno- 
mena which are presented by his land during the process 
of cultivation ; because a closer observation of each 
phenomenon will lead him to reflect upon the cause of 
it. This is the way to obtain an accurate knowledge of 
t]ie state and condition of the soil. 

Observation and reflection are the fundamental condi- 
tions of all progress in natural science ; and agriculture 
presents, in this respect, ample room for discoveries. 
What must be the feelings of happiness and contentment 
of the man who, by skilfully turning to proper account 
his intimate knowledge of the pecuharities of his land, 
has succeeded, without increased apphcation of labour or 
capital, in gaining from it a permanent increase of 
produce ? For such a result is not only a personal advan- 
tage to hunself, but a most important benefit conferred 
upon all mankind. 

Q 



226 THE SYSTEM OP FAEM-YAED MANUEING. 

How paltry and insignificant do all our discoveries and 
inventions appear, compared to what is in the power of 
the agriculturist to achieve ! 

AU our advances in arts and sciences are of no avail in 
increasing the conditions of human existence ; and though 
a small fraction of society may by their means be gainers 
in material and intellectual enjoyment, the load of misery 
weighing upon the great mass of the people remains the 
same. A hungry man cares not for preaching, and a 
child that is to learn anything at school must not be sent 
there with an empty stomach. 

Every step in advance, however, made by agriculture 
serves to alleviate the sufferings and troubles of mankind, 
and to make the human mind susceptible and capable of 
appreciating the good and the beautiful that art and 
science present to us. Improvements in agriculture con- 
stitute the only solid foundation for further progress in 
all other branches of knowledge. 

We now proceed to consider the changes brought 
about in the composition of the soil of a given field by 
cultivation by the system of farm-yard manuring. The 
cause to which the restoration of the power of produc- 
tion in the soil by farm-yard manure is attributable is 
the same in the case of all soils, without exception, how- 
ever widely the rotations may differ, or whatever be the 
nature of the crops cultivated upon them. 

By the cultivation of cereals, and the removal of the 
corn-crops, the arable surface soil loses a certain portion 
of corn-constituents, which must be restored to it by 
farm-yard manure, if the future crops are to be kept up 
to the mark of the preceding ones. 

This restoration is effected by the cultivation of fodder- 
plants, such as turnips, clover, grass, &c., on which the 
cattle oil the farm are fed, and the constituents of which 



MINEEAL MATTERS RESTORED BY MAJSTURE. 227 

are drawn, in large proportion, from tlie deeper layers of 
the ground, where the roots of the cereals cannot pene- 
trate. 

These fodder plants are consumed either on the field 
itself, as turnips in England, or in the stalls. A fraction 
of the nutritive substances contained in these plants 
remains in the body of the animals fed upon them, while 
the remainder, ejected in the form of solid or liquid 
excrements, constitutes farm-yard manure, the principal 
bulk of which, however, consists of straw which has 
served for litter. 

In Germany animals are not fed upon potatoes them- 
selves, but upon the refuse from the distilleries of potato 
spirits, which contains all the nutritive substances taken 
away from the soil in the potato crop, together with the 
constituents of the barley-malt that have been used in the 
process of mashing. 

Since the whole of the straw taken away in the crops 
of the preceding rotation is, as a general rule, returned 
to the arable soil in the shape of farm-yard manure, 
the field is, at the outset of the new rotation, as rich as 
before in the conditions for the production of straw ; 
and there exists, under these circumstances, no ground 
for a diminution of the straw-crops. 

With regard to the clover, turnips, potato- waste, &:c., 
upon which the stock on a farm is fed, there remains, as 
already stated, in the bodies of the horses, cattle, &c., and 
full-grown animals in general (which no longer materially 
increase in weight), only a very small fraction of the con- 
stituents of the food consumed ; but in the young cattle 
sent to market, in the bodies of the sheep, in the milk 
and cheese, a portion of these constituents is retained, 
which is not returned to the soil in the farm-yard manure. 
The loss of phosphoric acid and potash which the soil 

Q 2 



228 THE SYSTEM OP FARM-YARD MANURING. 

sustains by the sale of cattle and of animal products 
(wool, cheese, &c.), may be estimated at one-tenth of the 
quantity of these mineral constituents contained in the 
potatoes, turnips, or clover ; and even this estimate is, per- 
haps, too high. At all events, it is risking no great error 
to assume that nine-tenths of all the constituents of the 
clover, potatoes, or turnips, are returned to the field in 
the farm-yard manure ; whence the arable surface soil, 
after manuring, is richer for the new rotation in the mi- 
neral constituents of potatoes, clover, and turnips, than it 
was before, as the constituents of the two latter plants 
have been brought up from the deeper layers of the 
ground. 

The far greater portion of the active dung-constituents 
is retained by the upper layers of the soil, the deeper 
layers getting back very little of what has been taken 
from them ; the power of the latter, therefore, to produce 
as large crops of clover or turnips as before is not 
restored. 

The soil constituents which the animals have derived 
from the turnips, clover, potatoes, &c., and which remain 
in their bodies, are very nearly identical, in quantity and 
quality, with those of the cereals ; hence the loss sus- 
tained by the land may be estimated as equal to the corn- 
crops sold, plus the corn-constituents which the fodder- 
plants have given up to the animals on the farm. 

The restoration of the power of a field to produce a 
crop of corn as large as the last naturally presupposes 
that the conditions required for the production of the new 
crop should remain the same in the very layer of the soil 
which supphed the preceding crop ; in other words, the 
substances nutritive to corn which were taken away must 
be fully returned to the arable surface soil. 

If farm-yard manure contained only the constituents 



THE ELEMENTS OF FOOD IN FAEM-YAED MANUEE. 229 

of straw and potatoes, and nothing else, manuring a field 
with it could merely restore the productive power of the 
arable soil for straw and potatoes, but not for corn. 
Under these circumstances it would remain as rich as 
before in food elements for straw and potatoes, but would 
be poorer for corn to the extent of the whole quantity of 
corn-constituents taken away in the crops. 

If farm-yard manure is to restore the former pro- 
ductiveness of a field for corn, it must necessarily contain 
an amount of corn-constituents corresponding to the loss 
sustamed, that is to say, as much or even more than has 
been removed. 

The amount of the elements of food for corn contained 
in the farm-yard manure naturally depends upon the sum 
of these elements which have passed over into manure, 
from the cattle feeding upon clover or turnips. 

Where this supply exceeds the loss sustained, the 
arable soil is actually made richer in corn-constituents ; 
but in that case it is enriched also in the conditions for 
an increased produce of straw and tuberous plants. 
Where, therefore, the farm-yard manure (by the clover 
or turnip constituents in it) increases the amount of phos- 
phoric acid and nitrogen in the arable soil, it increases, 
in a much greater proportion, the quantity of potash and 
lime, and to some extent also that of silicic acid ; and 
since, as already stated, the whole of the straw-consti- 
tuents removed from the field are brought back to it in 
that manure, higher crops of corn, straw, and potatoes 
are the natural result. 

This increase of the produce of all cultivated plants 
drawing their principal food from the arable surface soil, 
may go on for a very long time, but in all fields it has a 
certain appointed limit. 

The time comes, sooner or later, for every field, when 



230 THE SYSTEM OF FAEM-YARD MANUEING. 

the subsoil (which is to the clover or turnips what the 

arable surface soil is to the cereals), suffering a continued 

drain upon its stores of phosphoric acid, potash, lime, 

magnesia, &c., begins to lose its productive power for 

clover or turnips ; and thus the nutritive substances, 

taken away from the arable surface soil in the corn crops, 

are no longer replaced from the store which existed in 

the deeper layers, and was brought up by the clover or 

the turnips. But the high returns of corn given by a 

field do not necessarily dechne with the incipient failure 

^ of the clover ; for where the arable soil of a field has, 

after every rotation, received from the clover or 

turnips more corn- constituents than it had lost by the 

corn-crop, there may be a gradual accumulation of an 

excess of these elements of food sufficient to conceal 

altogether from the farmer the true condition of his land. 

By introducing into his rotation vetches, white-clover, 

and other fodder-plants that derive their food from the 

upper layers of the soil, he succeeds in keeping up his 

live stock, and he indulges in the notion that all things 

go on in his field just as before, when the clover or the 

turnips yielded good crops. This is of course simply a 

delusion, as there is no longer an actual replacement of 

the loss sustained. His high corn-crops are now gained 

at the expense of the nutritive substances accumulated 

in excess in the arable surface soil wliich are set in 

motion by the fodder-plants introduced into the rotation, 

and are uniformly distributed again in the arable soil 

after each rotation, by means of the farm-yard manure. 

ffis dung-heap may happen to be of larger bulk and 
extent than formerly, but as there is now no further 
supply of nutritive substances brought up from the sub- 
soil or the deeper layers by the clover or turnips, the 
power of the manure to restore the original fertility of 



EESULTS OF PAEM-TAED MAN-UEING. 231 

the arable soil is continually decreasing. With the ulti- 
mate consumption of the excess of corn-constituents 
accumulated in the arable soil, the time comes when the 
corn-crop begins to diminish, whereas the produce of 
straw is comparatively higher than before, as the con- 
ditions for the formation of straw have been steadily 
increasing. 

Of course, the farmer cannot fail to remark the dimi- 
nution of his corn-crops, which induces him to have 
recourse to drainage, to improved tillage, and to the 
substitution of other cultivated plants, in lieu of clover 
and turnips. If the subsoil of his fields will permit it, 
he now includes in his rotation lucerne and sainfoin, 
whose still longer and more widely spreading roots 
enable them to reach yet deeper layers of the ground 
than the red clover ; until finally he employs the yellow 
lupine, which may truly be called the 'hunger-plant.' 

A new increase of produce is the result of these ' im- 
provements ' in his system of cultivation by farm-yard 
manuring, which the farmer looks upon as a great advance. 
A fresh store of nutritive substances, brought up from 
the deeper layers of the soil, may possibly accumulate 
again in the arable surface soil ; but these deeper layers 
also will be gradually exhausted, and the accumulated 
store in the arable surface soil will also be consumed. 

This is the natural termination of cultivation by the 
system of farm-yard manuring. 

The fields of the Saxon experiments afford very fair 
illustrations of the different conditions to which arable 
land in general is brought, by a pure system of farm- 
yard manuring. 

The field at Cunnersdorf is in the first stage, the 
Mausegast field in the second, the fields at Kotitz and 



232 THE SYSTEM OF PAEM-YARD MANUEING. 

Oberbobritzsch in the third stage, of cultivation by farm- 
yard manuring, to which we have referred. 

At Cunnersdorf the arable soil exhausted by the pre- 
ceding cultivation becomes with every new rotation 
richer in the conditions required for the production of 
grain ; not only does the clover replace the loss sustained 
by the removal of the corn-crops, but a remarkable 
excess of all nutritive substances will gradually accumu- 
late in the arable soil ; and, after a series of years, with 
the same system of cultivation by farm-yard manuring, 
the field will be brought to the condition of the land at 
Mausegast ; which means, that the arable soil will 
acquire a high productive power for corn and other 
crops, while the produce of clover will decrease. The 
fields at Kotitz and Oberbobritzsch most probably were 
in former times in the same condition as the Mausegast 
field is at present ; not that they ever yielded crops 
as large as the latter gives, but merely that the unma- 
nured plots have, at some antecedent period, given better 
crops than in the year 1851. Without an additional 
supply of mineral elements derived from meadows or 
other fields not included in the rotation, the produce 
must go on continually decreasing, as the supply of 
mineral constituents brought up by the clover from the 
subsoil, in these two places, is far from sufficient to make 
up for what is taken away in the corn-crops. 

In the following calculation it has been assumed that 
of the crops obtained, rye and oats were actually re- 
moved, and of potatoes and clover one-tenth was carried 
away in the form of cattle.* 

* The amount of phosphoric acid and potash is estimated in the 
calculation as follows : — 

Rye Oats Potatoes Clover-liay 

Corn Straw Corn Straw 

Phosphoric acid . . 0-864 0-12 075 0-12 0-14 0-44 

Potash .... 0-47 0-52 0-38 0-94 0-58 1-16 



MINEEAL MATTERS LOST IN CROPS. 233 



Gunner sdorf. 






Phosphoric acid 


Potash 


lbs. 


lbs. 


lbs. 


The arable soil lost by removal of 1176 rye-grain 


10-2 


5-5 


„ „ 2019 oats 


15-3 


7-7 


„ „ -^ potato crop 


2-3 


1-1* 


„ „ y^o clover crop 


4-0 


2-0* 



Total loss ..... 31-8 16-3 
The arable soil had returned to it, in ^ of 

9144 lbs. of clover-hay 36-18 95-5 

Balance in excess .... 4*38 79-2 

The arable soil of the Cunnersdorf field received, 
accordingly, in the farm-yard manure, more phosphoric 
acid and more potash than had been carried off by the 
corn-crops. 

In this calculation, it is a question of no imj^ortance 
how much of the rye or oats was carried off. More 
than the field produced could not be carried away, and 
if less were removed the only effect would be that 
phosphoric acid and potash would accumulate all the 
more in the field. 

Mdusegast. 

Phosphoric acid Potash 
lbs. lbs. 

The arable soil lost by the rye-grain, barley-grain, 

-^■^ potatoes, Jq- clover . . . . . 35'4 18*1 

The arable soil received in -^ of the clover crop 22'0 62*0 

Loss 13-4 Gain 43-9 

Kotitz. 

Phosphoric acid Potash 
lbs. lbs. 

The arable soil lost in the rye, oats, and in 

the ^L of the potatoes and clover . . , 26*4 12*7 

It received in the clover ..... 8"5 11-0 

Loss 17-9 T7 

The calculation is about the same for the field at 

*■ The quantity of potash is calculated here upon the proportion of 
phosphoric acid in corn, one part by weight of potash to two parts by 
weight of phosphoric acid. 



234 THE SYSTEM OF FARM-YARD MAJS^URING. 

Oberbobritzsch as for Kotitz. While the arable soil at 
Mliusegast, in consequence of the large clover crops pro- 
duced by it, still continues to gain in potash, the corn- 
crops are gradually reducing the rich store of potash in 
the Kotitz field. 

These three fields show the effect of a pure system of 
farm-yard manuring, from which is excluded all supply 
of manure extraneous to the farm itself. 

An additional supply of fodder purchased from other 
farms, or hay grown on natural meadows, answers the 
same purpose as an additional supply of manure. 

It is self-evident that we cannot give more farm-yard 
manure to a field than it produces, unless we take the 
constituents of the manure from some other field, which 
in that case must lose just as much as the former field 
gains. 

If we direct our attention to manured fields, we find 
that they give larger corn-crops, and in many cases also 
larger clover or turnip- crops ; the arable soil losing more 
by the removal of the corn-crop, and receiving more 
back by the increased produce of farm-yard manure, still 
the ultimate results remain the same. 

In the system of cultivating by rotation of crops, it is 
found that, for a long time, the arable soil grows with 
each period of rotation very much richer than it is by 
nature, in potash as well as in lime, magnesia (the prin- 
cipal constituents of clover and turnips), and in silicic acid. 

These substances are the principal conditions for the 
formation of roots and leaves ; their accumulation m the 
soil tends to make the ground rank and prone to grow 
weeds*, as the farmer says, an evil which arises as a 

* The most noxious of these weeds are the wild radish (Raphamis 
raphanistrum), the corn cockle {^Agrostemma cithago), the corn-flower 
or blue-bottle {Centaur ea cyanus)., the German camomile {Matricaria 



SUCCESSION OF CROPS IN ROTATION. 



235 



necessary consequence from cultivation by the system of 
farm-yard manuring, and which can only be met, as he 
thinks, by a rotation of crops. 

It is generally supposed that the best remedy is the 
hoe ; but though mechanical application may retard the 
developement of weeds for a time, it cannot effectually 
prevent them. The hoe has some share in removing 
them, but not all. 

The succession of crops in rotation is always made 
dependent upon the cereals ; the preceding crops are 
selected of such a kind that thek cultivation will not 
injure, but rather improve, the succeeding corn-crop. 
The selection of the particular kind, however, is always 
governed by the condition of the soil. 

In a field abounding in stalk and leaf constituents, it is 
often found useful to have wheat preceded by tobacco or 
rape, rye by turnips or potatoes, since these plants by 
drawino; from the soil a laro-e amount of leaf and stalk 

chamomilki), and the corn camomile (^Anthemis arvensis). All tliese 
plants contain, in their ash, as much potash as is found in clover, and 
7 to 18 per cent, of chloride of potassium, a salt which forms one of 
the principal constituents of the urine of animals, and which is brought 
to the field in the farm-yard manure. 





II. 


I. 










Matric. 


Matric. 


Anthemis 


Centaurea 


Agrostemma 


Per cent, ash . 


Cham. 


cham. 


arrensis 


cyanns 


cithago 


8-51 


9-69 


9-66 


7-32 


13-20 


The ash contains : 












Potash . 


25-49 


32-386 


30-57 


36-536 


22-86 


Chloride of 












potassium . 


18-4 


14-25 


7-15 


11-88 


7'o5 


Phosphoric acid 


5-1 


7-80 


9-94 


6-59 


6-64 


Phosphate of 












iron . 


2-39 


2-39 


4-77 


2-34 


1-80 



(EiJLiNG, 'Annal. d. Chem. und Pharm.' vol. Ivi. p. 122.) 



236 THE SYSTEM OP FARM-YARD MANURING. 

constituents serve to restore a more suitable proportion 
between the straw and corn constituents for the future 
cereal crop, and at the same time to diminish, in the arable 
soil, those conditions which favour the growth of weeds. 

The preceding observations relative to the produce 
given by the Saxon fields, both in the unmanured and 
manured state, afford, in my opinion, a perfect insight 
into the nature and results of cultivation by the system 
of farm-yard manuring. In the condition of these fields 
in their several stages, we may see reflected the history 
of agriculture. 

In the first period, or on a virgin soil, corn-crop is made 
to succeed corn-crop, and when the produce begins to fail, 
the culture is simply transferred to a fresh field. The 
increasing requirements of the growing population, how- 
ever, gradually put a check upon this plan, and compel 
a steady cultivation of the same surface ; a system of 
alternate fallowing is now resorted to, and efforts are 
made to restore the lost fertility of the soil, by manur- 
ing with the produce of the natural meadows. After 
a time, this expedient begins to fail, and leads to the 
cultivation of fodder-plants, the sub-soil being thus 
turned to account as an artificial meadow. The culti- 
vation of fodder-plants proceeds, at first, without inter- 
ruption ; after a time, longer and longer intervals are 
interposed between the clover and turni|) crops ; finally, 
the cultivation of fodder-plants comes to an end, and with 
it the system of cultivation by farm-yard manuring. The 
ultimate result is the absolute exhaustion of the soil, 
inasmuch as the means for increasing the produce of the 
soil gradually pass away from it by this system. 

Of course, the progress by which these different stages 
are reached is extremely slow, and the results are felt 
only by the third and fourth generation. When there 



PEESENT STAGE OF EUKOPEAN HUSBANDRY. 237 

are woods near the arable land, the peasant seeks to turn 
the fallen leaves to account as manure ; he breaks up 
the natural meadows which are still rich in elements 
of food for plants, and converts them into arable land ; 
then he proceeds to burn down the forests, and to 
manure his fields with the ashes. When the gradual 
exhaustion in the productive power of the land has led to 
a corresponding decrease in the population, the peasant 
cultivates his land once every two years as in Catalonia, 
or once every three years as in Andalusia.* 

ISTo intelhgent man who contemplates the present state 
of agriculture with an unbiased mind, can remain in 
doubt, even for a moment, as to the stage which hus- 
bandry has reached in Europe. We find that all coun- 
tries and regions of the earth where man has omitted to 
restore to the land the conditions of its continued fer- 
tility, after having attained the culminating period of the 
greatest density of population, fall into a state of bar- 
renness and desolation. Historians are wont to attribute 
the decay of nations to pohtical events and social causes. 
These may, indeed, have greatly contributed to the 
result ; but we may well ask whether some far deeper 
cause, not so easily recognised by historians, has not pro- 
duced these events in the fives of nations, and whether 

* The Emperor Charles V. gave orders that the meadows recently 
turned into arable land should be restored to their former condition. 
Even before the time of Charles V. orders of the same nature had been 
issued by the first Catholic Kings, and at a still earlier period by Pedro the 
Cruel of Castile. In the beginning of the fifteenth century, Henrique of 
Castile prohibited the exportation of cattle, on pain of death ; and as 
early as the commencement of the fourteenth century, King Alonzo 
Onzeno had issued ordinances for the preservation of meadows and 
pastm-es. ('Bilder aus Spanien von Karl Freiherrn von Thienen, Adler- 
fiycht.' Berlin : Dunker, p. 241.) All in vain ! for what avails the 
power of even the mightiest monarchs against the irrepressible action of 
a law of nature ? 



238 THE SYSTEM OF PAEM-YAED MANUEIISTG. 

most of the exterminating wars between different races 
may not have sprung from the inexorable law of self- 
preservation ? Kations, hke men, pass from youth to 
age, and then die out — so it may appear to the superficial 
observer; but if we look at the matter a little more 
closely, we shaU find that, as the conditions for the con- 
tinuance of the human race which nature has placed in 
the ground are very limited and readily exhausted, the 
nations that have disappeared from the earth have dug 
their own graves by not knowing how to preserve these 
conditions. Kations (like China and Japan) who know 
how to preserve these conditions of fife do not die out. 

Not the fertility of the earth, but the duration of that 
fertility, lies within the power of the human will. In 
the final result, it comes very much to the same thing, 
whether a nation gradually declines upon a soil constantly 
diminishing in fertihty, or whether, being a stronger race, 
it maintains its own existence by exterminating and 
taking the place of another people upon a land richer in 
the conditions of life. 

It can hardly be ascribed to caprice or chance that the 
cultivator in the huertas of Valencia obtains three crops 
yearly from the same soil, while in the immediate neigh- 
bouring district the ground is tilled only once in three 
years ; or that the Spaniards burned down forests in sheer 
ignorance, in order to u.se the ashes to restore the fertihty 
of their fields. (See Appendix G.) 

Everyone who is at all acquainted with the natural 
conditions of agriculture, must perceive that the method 
of culture practised for centuries in most countries could 
not but inevitably impoverish and exhaust even the most 
fruitful lands ; can it then be supposed that there Avill be 
any exception in the case of cultivated lands in Em^ope, 
and that like causes will not produce like effects ? 



FALSE DOCTRINES. 239 

Under these circumstances, is it right or reasonable to 
pay any attention to the doctrines of superficial wise- 
acres, who, with their wretched chemical analyses find an 
inexhaustible supply of nutritive substances in any given 
soil, even in one which can no longer produce clover, 
turnips, or potatoes, and yet may be rendered capable of 
producing these plants by manuring with ashes or lime m 
the right places ? 

In face of the daily experience which shows that the 
corn-fields, if they are to remain fruitful, must be 
manured after a short series of years, it is a crime against 
human society, a sin against the pubhc welfare, to dis- 
seminate the doctrine that the fodder-plants, which fur- 
nish manure to the corn fields, will constantly find upon 
the field the conditions of their own growth, that the 
law of nature applies to one kind of plant only, and has 
no bearing upon the other. The teaching of these men 
has no other result than to keep agriculture in the low 
position which it now occupies. In England it is a 
mere mechanical handicraft, and in that country manure 
is regarded as merely the oil which smoothes the wheels 
and keeps the machine in motion. 

In Germany agriculture is a jaded horse, treated with 
blows instead of fodder ; nowhere is its real beauty and 
the intellectual aspect of its pursuit recognised. JSTot 
merely for its utility, but on account of this very intellectual 
nature of its pursuit, it stands above all occupations ; and 
its practice procures, to the man who understands the 
voice of nature, not only all the advantages for which he 
strives, but also those pleasures which science alone can 
afford. 

In human society, ignorance is undoubtedly the fun- 
damental, and therefore the very greatest evil. The igno- 
rant man, however rich he may be, is not protected from 



240 THE SYSTEM OF FARM-YAED MAKUEING. 

poverty by liis wealth ; while the poor man, who has 
knowledge, becomes rich by its means. Unconsciously 
to the ignorant farmer, all his industry, care, and toil only 
hasten his ruin ; his crops gradually diminish, and at 
length his children and grandchildren, no wiser than 
himself, are unable to maintain themselves upon the 
homestead where they were born ; their land passes into 
the hands of the man who has knowledge ; for by know- 
ledge capital and power are acquired, and by these, as a 
matter of course, the helpless are expelled from the inhe- 
ritance of their forefathers. 

As an animal cannot care for himself, the law of 
nature takes care of him, and is his master ; but not so 
with man, who, if he understands the intentions of God 
in his creation, is master of the law of nature, which 
yields to him a complete and willing obedience. The 
animal brings into the world his perceptions and instincts, 
which grow up with his growth, and without any effort 
of his own ; but to man the Creator gave the gift of 
reason, and this distinguished him from the brutes. This 
is the divme talent, which he should put out to interest, 
and of which it is said, ' He that hath, to him shall be 
given ; but from him that hath not, shall be taken away 
even that which he hath.' It is only the interest pro- 
cured by means of this ' talent ' that gives man power 
over the forces of the earth. 

Error arising from want of knowledge is excusable, for 
no one adheres to it after recognising its existence ; and 
the struggle between error and dawning truth arises 
from the natural striving of men for knowledge. In 
this contest truth must grow stronger, and if error pre- 
vails, this only proves that truth has yet to grow, not that 
error is truth. 

At all times the ' better' has always been the enemy 



COEN NOT INCREASED BY FARM-YARD MANURING. 241 

of the ' good ; ' but men do not comprehend for all that 
why, in so many cases, ignorance is the enemy of reason. 

There is no profession which for its successful practice 
requires a larger extent of knowledge than agriculture, 
and none in whicli the actual ignorance is greater. 

The farmer who practises the system of rotation, 
depending exclusively upon the application of farm-yard 
manure, needs very httle observation, nay only to open his 
eyes, in order to be convinced, by innumerable proofs, that 
whatever may have been the outlay of labour and industry 
applied to the production of farm-yard manure, his fields 
have not been thereby increased in the power of bearing 
crops. 

If farm-yard manure was actually able to render a 
field permanently richer in nutritive substances than it is 
by nature, we might expect that a course of manuring 
for fifty years would necessarily produce a steady increase 
in the crops. 

Now, if farmers who practise the system of rotation, 
laying aside all bias and prejudice, would compare their 
present with their former crops, or with those obtained 
by their fathers or grandfathers, none of them would 
be able to say that the crops have mcreased, and only 
few that the average has remained the same. Most of 
them would find, that on the average, the straw-crops 
have turned out higher, but the corn-crops lower, and 
proportionately lower than they formerly were higher ; 
and that the surplus money which their parents gained by 
the former high crops, the result of their improvements, 
as they supposed, must now be paid out again, to pur- 
chase manuring substances, which, as people formerly 
thought, could be ' produced.' Now, however, they begin 
to learn that though such substances may be produced 
for a time they cannot be reproduced in perpetuity. 



242 THE SYSTEM OF FAEM-YARD MANURING. 

In like manner, the farmer whose richer gromid has 
enabled him to carry out the three-field system, and 
whose rich meadows guarantee a supply of manure, who 
obtains as abundant harvests and as large a weight of 
corn as the farmer who adopts the system of rotation, 
and thus surmises that his management has procured 
what the ground gives of its own free will, will inevitably 
discover that his fields may be exhausted of the condi- 
tions of their fertility, and that it is quite erron )us to 
suppose that all the farmer's art consists in concerting 
manure into corn and flesh. 

A simple law of nature regulates the permanence of 
agricultural produce. If the amount of produce is in 
proportion to the surface presented by the sum total 
of nutritive substances in the soil, the permanence 
of the crops will depend upon the maintenance of that 
proportion. 

This law of compensation, the replacement of nutritive 
substances which the crops have carried away from the 
soil, is the foundation of rational husbandry, and must, 
above all things, be kept in view by the practical farmer. 
He may renounce the hope of making his land more 
fruitful than it is by nature, but he cannot expect to keep 
his harvests up to their average if he allows the necessary I 
conditions for them to diminish in his land. i 

All those farmers who cherish the notion that the ' 
produce of their fields has not declined, have not hitherto | 
been able to appreciate the force of this law. Assuming i 
that they have an excess of nutritive substances to deal \ 
with, they think they may continue drawing upon it, i 
until a failure becomes \dsible, and then they fancy it^ 
will be time enough to talk of compensation. ' 

This view results from want of understanding the!'! 
nature of their own acts. i 



EECOEDS OF CHAKLEMAGNE. 243 

There surely can be no doubt that to manure a field 
which already contains an excess of nutritive substances, 
is opposed to a rational system of cultivation ; for vi^hat 
end could be gained by increasing the nutritive substances 
in a field where a portion of the elements already existing 
cannot, on account of their mass, come "into operation? 

But how can sensible men talk of excess when they are 
obhged to use manure in order to keep up their harvests, 
and w m their crops dechne if they employ no manure ? 

The ample fact, say others, that in certain districts, as 
in Ehenish Bavaria, agriculture has flourished since the 
time of the Eomans, and that the ground there is just as 
rich, nay, gives higher crops than in other lands, is a 
proof how httle reason there is to fear want or exhaus- 
tion by continued culture ; for if such a thing were 
likely, it would make itself manifest there sooner than 
elsewhere. 

But in the cultivated lands of Europe agriculture is at 
all events still very young, as we know vdth the greatest 
certainty from records of the time of Charlemagne. His 
ordinances respecting the management of his own estates 
[capitulare de villis vel curtis imperatoris)^ wherein 
directions are given to the stewards, as also the ofiicial 
reports to the Emperor [specimen hreviarii rerum Jisca- 
lium Caroli Magni), sent in by inspectors expressly 
appointed to survey those estates, are irrefragable proofs 
that there was then no agriculture worth the name. 
Very little is said in the Capitulare about the cultivation 
of corn, vdth the exception of millet. It is reported in 
the Breviarium, that at Stefanswerth (a domain of the 
Emperor), comprising 740 acres (jurnales) of arable 
land and meadow, capable of supplying 600 cartloads of 
hay, the commissioners found no corn in store, but on 
the other hand a large number of cattle, 27 sickles great 

R 2 



244 THE SYSTEM OF FAEM-YARD MANURING. 

and small, and only seven broad hoes, to till 740 acres 
of land! 

Upon another estate were found 80 baskets of last 
year's spelt, equivalent to 400 lbs. of flour (=1 J bushel, or 
somewhat more than 3 hectolitres), 90 baskets of spelt 
of the current year, from which 450 lbs. of flour could 
be made. On the other hand^ there were 330 hams! 

The crop or stock upon another domain amounted to 
20 baskets of spelt (=100 lbs. of flour) of the preceding 
year, and 30 baskets of spelt, of which one was used 
for seed. 

It is easy to see that in those days the breeding of 
cattle was the chief object, and that the cultivation of corn 
occupied a very subordinate position in husbandry.* A 
deed of the period shortly after Charlemagne says on 
this point : ' Every year three yokes of land upon an 
estate ' should be ploughed and sown with seed fur- 
nished by the lord of the manor. (See ' die Getreide- 
Arten und das Brod von Freih. von Bibra.' Nurem- 
berg : Schmid. 1860.) 

Hence we possess not a single trustworthy proof that 
any one field in Germany or France (perhaps we may 
make an exception in favour of Italy) has served for the 
cultivation of corn from the time of Charlemagne to our 
own age ; and the argument for the inexhaustibility of 
land is almost childish, because it assumes that corn may 
be continuously taken from a field, ivithout restoring tlie 
conditions of reproduction. A field does not necessarily 
become unfruitful for corn because it has yielded large 
corn-crops ; but it ceases to yield corn-crops if it does 
not receive compensation for the corn-constituents which 

* It is worthy of remark tliat Charlemagne introduced, iijion his 
estates, the three-field system, with which he had become acquainted in 
Italy. 



EXHAUSTION OF EHENISH BAVAEIA. 245 

have been removed. This compensation is facihtated by 
the breeding of cattle, m proportion to the extent to 
which this is carried, and especially when the cultivator 
is acquainted with the operation of manure. In the 
time of Charlemagne this was well known, for the whiter- 
crops were manured with dung, distinguished as cattle- 
dung (called gor) and horse- dung [dost or deist). Besides, 
the practice of marling was then common in Germany. 

With regard to the special instance of Ehenish Bavaria 
as proving the inexhaustibility of the soil, I had an 
opportunity last autumn, at a meeting of the Society of 
Katurahsts at Spires, of making particular inquiries 
about the actual condition of the neighbourhood. Ehe- 
nish Bavaria, from the slopes of the Hardt mountains to 
the Ehine, comprises a district of great fertility: the 
region is inhabited by an extremely industrious popula- 
tion, distributed in small towns and villages. Almost 
every artisan, even to the tailor and shoemaker, possesses 
a small plot of ground, on which he raises his potatoes 
and vegetables. The export of corn from this district is 
never thought of, but on the contrary corn and a large 
quantity of manure are imported from Mannheim, Hei- 
delberg, and elsewhere. The manuring substances ob- 
tained from the houses of the towns and villages are 
carefully treasured and employed, so that there can be 
no fear of exhaustion, since the removed nutritive sub- 
stances are restored to the fields. In spite of all this, in 
no part of Germany is the want of manure more felt 
than there. On the highways children are constantly 
seen with little baskets, following the horses and swine, 
to gather the manure dropped by those animals. In the 
year 1849, during the pohtical agitation in the Palatinate, 
the peasants had no more urgent request for the im- 
provement of their condition to lay before the magistrates, 



246 THE SYSTEM OP FARM-YAED MANURING. 

than a petition to be allowed to collect ' forestings,' 
that is, to carry off the natural manure from the 
forests for the benefit of their fields. They urged that 
without this (very pitiful) addition to their manure, the 
future prospects of agriculture in the Palatinate were 
endangered. In fact, a great quantity of manure is laid 
out upon the vineyards and tobacco-fields, which give 
none in return ; hence the increasing want. 

There can be no doubt that in the earliest periods 
most of our cultivated fields gave a succession of abundant 
crops, without manuring, as is the case even now with 
many fields in the United States of America. But no 
fact has ever yet been more clearly established by expe- 
rience than this, that in the course of a few generations 
all such fields are found perfectly unsuited for the growth 
of wheat, tobacco, and cotton, and that they recover 
their fertihty only by manuring. 

I know full well that recorded facts have as little 
weight with ignorant 'practical men' as those of poh- 
tical history with practical statesmen, who also act 
according to ' circumstances and contingencies,' and are 
simply led when they fondly believe they lead. Still, the 
reflecting mind cannot fail to be struck by the cu-cum- 
stance, that it is just in countries where the land is most 
positively known to have given for above 4000 years, 
without manuring by the hand of man, an uninterrupted 
succession of abundant crops, that the full action of the 
great law of restitution is most clearly seen. 

We know, most positively, that the corn-fields in the 
valley of the Nile and the basin of the Ganges remain 
permanently fruitful, simply because nature has taken 
upon herself to restore the lost condition of productive- 
ness to the soil in the mud deposited by the inundation 
of these rivers which gradually raises the land. 



THE SOIL NOT INEXHAUSTIBLE. 247 

All the fields that are not reached by the river lose 
their productiveness unless manured. In Egypt, the 
amount of the crop to be expected is calculated from the 
height of the water of the Nile ; and in the East Indies 
a famine is the inevitable consequence whenever there 
happens to be no inundation. 

Nature herself, in these striking instances, points out to 
man the proper course of proceeding for keeping up the 
productiveness of the land. (See Appendix H.) 

The notion of our ignorant practical husbandmen, that 
the soil contains ample store of the elements of food to 
enable them to pursue their system of agriculture, is due 
partly to the excellent quality of the land, but also to 
their skill in robbing it. The man who attempts to gain 
money by fihng the weight of one gold piece from a 
thousand, cannot plead, in extenuation, that it is re- 
marked by no one, but if discovered he is punished by 
the law; for everybody knows that the fraudulent act, 
repeated a thousand times, would ultimately leave nothing 
of the gold pieces. A similar law, from which, more- 
over, there is no escape, punishes the agriculturist who 
would make us believe that he knows the exact store of 
available food elements in his land, and how far it will go ; 
and who deceives himself when he fancies he is enriching 
his field by bestowing on the arable surface soil the 
matters taken from the deeper layers. 

There is another class of agriculturists consisting of 
men with a small stock of knowledge joined to a limited 
understanding, who, indeed, fully recognise the law of 
restitution, but interpret it after their own fashion. They 
assert and teach that part of the law only, and not the 
whole, applies to cultivated fields ; that certain consti- 
tuents, unquestionably, must be restored to the soil to 
keep up its productiveness, but that all the others are 



248 THE SYSTEM OF FARM-YAED MANUEING. 

found in the earth in inexhaustible quantities. They 
generally base their opinion upon some unmeaning che- 
mical analysis, and demonstrate to the simple agriculturist 
(for whom alone such disquisitions are intended) how 
rich his fields still are in some one or other of the mine- 
ral constituents, and for how many hundred thousand 
crops the store will still suffice ; as if it could be of the 
least use for any one to know what the soil contains, if 
the amount of the available food elements that serve to 
produce the crops, which is the really important point, 
cannot be determined. 

With such absurd assertions they absolutely hoodwink 
our ' practical ' farmers, who, but for them, might see 
clearly into matters, but who appear only too wilhng to 
accept any assertion that will only leave them at peace, 
and save them the trouble of ' thinking.' 

I remember a case where a swindler offered to sell to 
a wealthy gentleman, at a high price, a mine of almost 
pure oxide of aluminiinn, after having shown him, from 
chemical works, that oxide of aluminium was indispen- 
sable for the production of the metal aluminium, the 
market price of which was as much as 4:1. per pound, 
and that the ore of the mine offered for sale con- 
tained nearly 80 per cent, of that valuable metal. The 
purchaser was not aware that the ore m question is gene- 
rally kno^vn as ' pipe-clay,' an article of almost nominal 
value, and that the high price of the metal arises from 
the many changes through which the oxide has to pass 
to effect its reduction to the metaUic state. 

It is generally the same with the great stores of potash 
in the soil. The alkali in the ground, to answer the 
intended purpose, must, by the agriculturist's art, be con- 
verted first into a certain form, in which, alone, it is 
available as food for plants ; and if he does not under- 



IGNORANT PRACTICAL MEN. 249 

stand how to effect this conversion, all the potash in his 
soil is of no earthly use to him. 

The notion that the farmer need only restore to his 
land certain substances, without troubling himself about 
the rest, might not be prejudicial if those who entertained 
it confined the appUcation to their own farms ; but, as a 
matter of instruction to others, it is untrue and quite 
exceptionable. It is calculated for the low intellectual 
standard of the practical man, who, if he in any way 
succeeds, by certain alterations, in his system, or by the 
use of certain manuring agents in obtaining better results 
than another, attributes his success to his own sagacity 
rather than to the superior quality of his land. He does 
not even know that the other has tried the very same 
plans as himself, only without attaining so favourable a 
result. Our ignorant practical husbandman starts upon 
the assumption that all fields are the same in condition as 
his own, and that, therefore, the same system which 
answers on his farm ought to do equally well on every 
other ; that the manure which he finds useful ought to be 
equally useful to others ; that the deficiencies in his field 
are the same in all other fields ; that what he exports 
from his land, others export from theirs ; and what he is 
called upon to restore to his soil, others are equally called 
upon to restore to theirs. 

Although he knows next to nothing of the condition 
of his own land, with which it woidd, indeed, require 
many years of careful observation to become familiar, 
and is most profoundly ignorant about the condition of 
the land in any other part, although he never has 
troubled himself with reflecting upon the causes of his 
success in the cultivation of his fields, and is quite aware 
that the advice of agriculturists from other parts, re- 
specting manuring, rotation of crops, and the general 



250 THE SYSTEM OF PARM-YAED MANURING. 

treatment of his own land, is not of the shghtest use to him, 
because, as he has found, it is not at all applicable to his 
district ; yet all this does not prevent him from wanting to 
instruct others, and persuade them that his system is the 
only true one, and that they need only do as he does to 
obtain equally favourable results. 

The foundation of all such views is a total miscon- 
ception of the nature of the soil, the condition and com- 
position of which presents an infinite variety of shades. 

The fact that many fields that happen to be rich in 
sihcates, and in lime, potash, and magnesia, are, by the 
growth of corn upon the common farm-yard manuring 
system, drained only of phosphoric acid and nitrogen, 
and that the farmer need only look to the replacement of 
these matters without troubling his mind about the rest, 
has already been fully discussed. This fact no one can 
dispute : but it is utterly inadmissible to apply it to the 
case of other fields, and to make other farmers beheve 
that they, too, need not trouble their minds about supply- 
ing to their land potash, lime, magnesia, or silicic acid, 
and that salts of ammonia and superphosphate of lime 
win sufiice to restore the productiveness of all exhausted 
fields. 

A farmer may, therefore, be quite justified in consider- 
ing that his field can never grow poorer in potash because 
he never takes any from it, or that it actually contains a 
superabundance of potash since every rotation tends to 
accumulate in the soil a fresh amount of that insredient : 
but it is childish of him to think himself justified by this 
circumstance in assuring another agriculturist, about 
whose system of cultivation he knows nothing, that the 
fields of the latter equally contain a superabundance of 
potash. 

There are millions of acres of fertile land (sand and 



MATTERS TO BE RESTORED VARY. 251 

clay-soil), in which the proportion of lime or magnesia in 
the soil does not exceed that of phosphoric acid, and 
where provision must be made for replacing the former 
as well as the latter. Agam, there are milhons of acres 
of fertile land, which, like calcareous soils in general, 
are exceedingly poor in potash, and become absolutely 
barren without a proper supply of this ingredient. 

There are, on the other hand, millions of acres of 
fertile jBields abounding so richly in nitrogen that any 
additional supply of that element would be mere waste. 

Ashes will not promote the growth of clover on fields 
abounding in potash, whilst the application of manuring 
agents containing phosphoric acid will have that effect ; 
on the other hand, ashes will make clover grow on land 
deficient in potash, where bone-earth proves useless ; and 
a simple supply of lime containing magnesia will often 
suffice to restore the productiveness for clover where the 
land is deficient in hme and mamesia. 

o 

When a farmer, besides corn and flesh, grows and sells 
other produce, the nature of the requu-ed supply of 
mineral elements is thereby necessarily altered. In the 
average potato produce of three hectares of land we 
take away the seed-constituents of four wheat crops, 
besides about 600 lbs. of potash, and in the average 
turnip produce of three hectares the seed-constituents of 
four wheat-crops, besides about 1000 lbs. of potash. A 
supply of phosphoric acid alone will not suffice, in this 
case, to keep up the productiveness of the land. 

The grower of commercial plants, such as tobacco, 
hemp, flax, the vine, &c., must in Hke manner strictly 
attend to the law of restitution, Avhich, properly inter- 
preted, does not imply that he should bestow the same 
anxious care upon the replacement of all constituents 
ahke which have been taken away in the crops. It 



252 THE SYSTEM OF FAEM-YARD MANUEING. 

would, for instance, be the lieiglit of absurdity to require 
the tobacco planter who grows his crops on a lime or 
marl soil, to replace the lime carried off in the leaves of 
the plant. But it tells him that not all that goes by the 
name of manure is useful for his fields, and it shows him 
the difference between manures : it informs him of the 
loss inflicted upon the soil by the preceding crop, and 
the supply required to insure future harvests ; it teaches 
him never to allow himself to be guided in his proceed- 
ings by the opinions of persons who do not take the 
slightest interest in him and his land, but always to act 
upon his own observations. A careful study of the weeds 
that spring up spontaneously in his fields may frequently 
prove more useful in this respect than a heap of hand- 
books on agriculture. 

If after the foregoing statements the condition of the 
cultivated land in Europe, and the decline towards which 
agriculture is tending by the prevaihng system of farm- 
yard manuring, should still be a matter of doubt to 
many persons unacquainted with the natural sciences, 
and who trust only to definite numbers as palpable facts, 
that doubt may, perhaps, be removed by statistical data 
on the corn produce of the land in different parts of 
Germany, which have been collected partly by order of 
the government. 

For a correct appreciation of the importance of these 
data in the matter, it is necessary in the first place to 
understand clearly what is meant by an ' average' crop. 
By this term is designated the average produce, ex- 
pressed in numbers, of a field, or a number of fields, or 
all the fields of a district or country. The figure which 
represents it is found by adding together the produce of 
all the fields for a number of years, and dividing the 
sum total by the latter. There is accordingly a special 



MEANING OF AVEKAGE CKOP. 253 

average produce for every district, by which the next 
year's crop is judged. Thus we talk of a full, or a half, 
or a three-quarter average, as the produce happens to 
come up to the calculated average, or fall one-half or 
one quarter below it. 

The question as to the actual condition of our corn- 
fields may therefore be put thus : Has there been any 
change in the figure which at any previous period ex- 
pressed the average produce of the land, and in what 
sense ? Is that figure higher now than formerly, or has 
it remained the same or fallen ? If the figure is higher, 
this is of course a sign of an improved condition of the 
land ; if it remains the same, the condition has under- 
gone no change ; and if it is lower, there can be no 
doubt that the condition of the land in that district has 
declined. 

I select for my purpose the statistical data of the pro- 
duce of the Hessian Ehine district, one of the most 
fertile provinces of the Grand Duchy of Hesse, with an 
excellent wheat soil, and inhabited by a most industrious 
and generally well educated population. (' Statistische 
Mittheilungen iiber Eheinhessen, von F. Dael, DLL.' 
Mayence : 1849. Flor. Kupferberg.) 

These data embrace a period of fifteen years, from 
1833 to 1847 ; they refer accordingly to the time when 
guano was not yet used as manure in Germany. The 
use of bone-earth was at that time also still very limited, 
and hardly worth taking into account. 

A produce of eleven grains of wheat to every two 
grains sown, of five and a half accordingly, was held 
to be an average crop for the Hessian Ehine district. 
(20 malters^l4 bushels=5120 hectolitres per hectare 
=2-471 English acres.) 

Taking the figure 1 to express an average crop, the 



254 THE SYSTEM OP FAEM-YAED MANUEINQ. 

amount of produce reaped in the Kliine district of Hesse 
was : — 



1833 


1834 


1835 


1836 


1837 


1838 


1839 


0-85 


078 


0-88 


0-72 


0-88 


0-73 


0-61 


1840 


1841 


1842 1843 


1844 


1845 


1846 


1847 


1-10 


0-40 


0-90 0-74 


1-02 


0-63 


0-75 


0-88 



wMch gives a mean for the fifteen years of 0-79 of the 
former average. 

The productiveness of the wheat land in the Rhine dis- 
trict of Hesse has therefore declined somewhat more than 
onefifth. 

I know all that may be urged against the accuracy of 
these figures severaUy, and their trustworthiness collec- 
tively ; but if they contain errors, the impartial observer 
must see that these must tend to the plus as well as to 
the minus side, and that it would be most extraordinary 
in the presence of p)lus errors that all the estimates 
should have fallen out on the minus side. 

There is, however, a very simple, and at the same time 
infallible and irrefutable, proof of the correctness of the 
conclusions drawn from these figures, in the fact that the 
cultivation of wheat is on the decrease, that of rye on 
the increase, in Ehine Hesse, and that many fields on 
which wheat was formerly grown are now turned into 
rye fields. 

Properly understood, the change from wheat to rye 
always argues a deterioration in the quahty of the soil ; 
the farmer begins to grow rye in a wheat field only when 
the latter no longer gives remunerative wheat crops. 

In Ehine Hesse, a 4 J fold produce of rye is considered 
an average crop ; a wheat soil, therefore, capable of 
giving only four-fifths of an average wheat-crop, can pro- 
duce a fuU average rye-crop. 

Now the average produce of rye in the fifteen years is 



DETERIORATION OF ARABLE SOIL. 255 

0-96, wMcli pretty nearly corresponds with the full 
average. 

For spelt, the mean was 0-79 of the average ; for 
barley, 0-88 ; for oats, 0-88 ; for peas, 0-67 ; for pota- 
toes, on the other hand, 0*98 ; and for colewort and 
turnips, 0*8 5. 

The statistical data collected in Prussia and Bavaria, 
which are most reliable, give the same result ; and I 
have not the slightest doubt that it would hold equally 
true with France and other countries, England included. 
The visible gradual deterioration of the arable soil 
cannot but command the serious attention of all men 
who take an interest in the pubhc welfare. It is of the 
utmost importance that we do not deceive ourselves 
respecting the danger, indicated by these signs, as threat- 
ening the future of the populations. An impending 
evil is not evaded by denying its existence or shutting 
our eyes to the signs of its approach. It is our duty to 
examine and appreciate the signs : if the source of the 
evil is once detected, the first step is thereby taken to 
remove it for ever. 



266 



CHAPTEE VI. 

GUANO. 

Composition compared with that of seeds ; small amomit of potash in it ; 
its action — Guano and bone-earth, similarity of their active ingredients 
— Guano acts quicker than bone-earth, or a mixture of the latter and 
ammouiacal salts ; reason of this — Oxalic acid in Peruvian guano ; the 
phosphoric acid rendered soluble by its means — Peruvian guano, its effect 
on the cultivation of corn — Moist guano loses ammonia — Moistening 
guano with water acidulated with sulj)huric acid ; effect — Inactivity of 
guano in dry and very wet weather — Rapidity of its action as a manure, 
on what dependent — Comparison of the effect of farm-yard manure 
and guano ; effect produced by mixing the two — Guano on a field rich 
in ammonia — Increased produce by guano, what it presupposes — 
Exhaustion of the soil by continuous use of guano — Mixture of guano 
with gypsum and with sulphuric acid — The Saxon agricultural experi- 
ments ; their results. 

PEEUVIAJSF guano generally contains 33 to 34 per cent, 
of incombustible, and 66 to 67 per cent, of volatile 
and combustible ingredients (water and ammonia). The 
latter consist principally of uric acid, oxalic acid, a brown 
matter of uncertain composition, and guanine. The 
uric acid amounts occasionally to as much as 18 per 
cent., the oxalic acid generally to 8 or 10 per cent, of 
the weight of the guano. The relation of uric acid to 
vegetation is not known, but it is hardly likely that this 
substance can have a perceptible share in the fertilising 
action of guano. To account for this action, then, 
we have only the ammonia and the incombustible con- 
stituents left to consider. An analysis of two samples of 
guano, made by Dr. Mayer and Dr. Zoeller, in my own 
laboratory, showed 100 parts of guano ash to contain : — 



ASH OF GUANO AND SEEDS COMPAEED. 257 

Potash 1-56 to 2-03 

Lime . . . . . . 34-00 „ 37-00 

Magnesia 2-56 „ 2-00 

Phosplioric acid .... 41-00 „ 40-00 

If we compare with this the composition of the ashes 
of various seeds, we see at once that the incombustible 
constituents of guano do not ahogether replace the soil 
constituents carried off in the seeds. 

In 100 parts of seed ash are contained, — 





Wheat 


Peas and beans 


Rape 


Potash . 


. 30 


40 


24 


Lime 


. 4 


6 


10 


Magnesia 


. 12 


6 


10 


Phosphoric acid 


. 45 


36 


36 



The principal difference between the ash of guano 
and that of these seeds lies in the deficiency of potash 
and magnesia in the former. 

Agriculturists are generally agreed about the necessity 
of potash for vegetation, and that a supply is required by 
fields poor in that ingredient, or drained of it ; but the 
question as to the importance of magnesia for seed for- 
mation has not, as yet, met with the same attention, and 
special experiments in this direction would be very desir- 
able. The fact that much more magnesia is found in the 
seeds than in the straw unmistakably shows that it must 
play a definite part in the formation of the seed, which 
might, perhaps, be ascertained by a carefiil examination 
of seeds of the same variety of plants containing different 
amounts of magnesia. It is a well-known fact that the 
seeds of the several species of cereals having the same 
proportion of nitrogen, do not always contain the same 
nitrogenous compounds, and it is possible that the nature 
of the latter may, in the formation of the seeds, be essen- 
tially influenced by the presence of hme or of magnesia, 
so that the differences in the proportions of both of these 



258 GUANO. 

alkaline earths may have a certain connection with the pre- 
sence of the soluble nitrogenous compounds (albumen and 
casein), or of the insoluble (gluten or vegetable fibrine). 
Of course, the quantity of potash and soda present would 
have to be taken into account in an investigation of the 
kind. The fertihsing action of guano is generally attri- 
buted to the ammonia in it, and to the other ingredients 
rich in nitrogen ; but accurate experiments made to elu- 
cidate this point, by the General Committee of the Agri- 
cultural Society of Bavaria, which we shall hereafter have 
occasion to mention, have shown that whilst the use of 
guano was found, in many cases, to increase very con- 
siderably the produce of corn and straw of a field, the 
apphcation of an ammoniacal salt containing an amount 
of nitrogen corresponding to that in the guano produced 
no perceptible effect on the crop of the same cereal, 
grown in the same year, upon another plot of the field, 
when compared with the produce of a third unmanm-ed 
plot of the same field. 

Though the part which the ammonia in the guano 
plays, in many cases, in increasing the produce, cannot 
be questioned ; yet it is equally certain, on the other 
hand, that in many other instances the fertilising action 
of guano must be attributed principally to its other con- 
stituents. 

If the ash of guano is compared with calcined bones, 
or bone-earth, it is fomid that the difference between the 
two is not very great; yet an amount of bone-earth 
containing the same proportion of earthy phosphate as in 
guano, or even two to four times that quantity, has not 
the same action as the latter manure. Even a mixture of 
bone-earth with ammoniacal salts in sufiicient proportion 
to make the amount of nitrogen and phosphoric acid 
equal to that contained in the guano, though more 



OXALATE OF AMMONIA IN GUANO. 259 

efficacious than bone-earth alone, has still a different action 
from guano. The great distinction between the two lies 
in the greater rapidity of the action of the guano in the 
first year, and often even in the course of a few weeks, 
whilst in the year after it is barely perceptible ; that of 
the bone-earth, on the other hand, is comparatively slight 
in the first year, but increases in the following. 

The cause of this difference of action is the oxalic acid 
in Peruvian guano, which often amounts to from 6 to 10 
per cent. If guano is subjected to lixiviation, the water 
dissolves sulphate, phosphate, and oxalate of ammonia, 
which latter salt crystallises out abundantly upon evapo- 
rating the solution. But if the guano is moistened with 
water, without lixiviating, and is then left to itself, it is 
found, upon extracting with water portions of the mix- 
ture from time to time, that the proportion of the oxalic 
acid in the solution gradually decreases, whilst that of 
the phosphoric acid increases. A decomposition takes 
place in this moistened condition of the guano, through 
the agency of the sulphate of ammonia, by Avhich the 
phosphate of lime is converted into oxalate of lime and 
phosphate of ammonia. Peruvian guano is, in this 
respect, a very remarkable mixture, which could scarcely 
have been more ingeniously compounded for the purposes 
of the nutrition of plants ; for the phosphoric acid in it 
becomes soluble only in a moist soil, through Avhich it 
then spreads in form of phosphate of potash, phosphate 
of soda, and phosphate of ammonia. 

The action of guano may rather be compared to a 
mixture of superphosphate of lime, ammonia, and salts 
of potash, which, indeed, in many cases, is equal to it. 
On a soil abounding in lime, guano is, however, decidedly 
more advantageous than superphosphate of hme, since 
the latter, upon coming in contact with the carbonate of 



260 GUANO. 

lime in the soil, is at once converted into neutral 
phosphate of lime, which requires to meet with another 
solvent at the place of formation to effect its diffusion 
through the soil, whilst phosphate of ammonia spreads 
through a lime soil just as if there was no carbonate of 
hme in it. The phosphate of ammonia formed when 
guano is moistened with water (PO5 + 3NH4O), loses in the 
air one-third of the ammonia. It is owing to this circum- 
stance that guano, when quite dry, will keep without 
alteration ; whereas, when it has been fraudulently moist- 
ened, to increase the weight, it loses, by keeping, con- 
siderably in ammonia. 

If guano, just before its application on the field, is 
moistened with water and a little sulphuric acid, suffi- 
cient to give the water a slightly acid reaction, the decom- 
position now mentioned, which otherwise requires days 
and weeks, is effected in a few hours. 

That guano should not produce much effect in very 
dry weather needs no explanation, because, without 
water, no substance will act in the ground ; that it 
should, however, equally fail in very wet weather, is, 
undoubtedly, owing in part to the fact that the oxahc 
acid is washed out, as an ammoniacal salt, by the rain 
water, and that there is, accordingly, a corresponding quan- 
tity of phosphoric acid not made soluble. By the above 
simple and cheap means the injurious influence of wet 
weather upon guano may be completely guarded against, 
inasmuch as the water and sulphuric acid ensure the con- 
version into a soluble form of the whole of the phos- 
phoric acid, which could have been brought into that 
condition by the oxalic acid. 

The rapidity with whicli a nutritive substance employed 
in the shape of manure produces an effect, depends 
essentially upon the speed with which it spreads through 
the soil, and this, again, upon its solubility ; hence it is 



ADDITION OF GUANO TO FAEM-YARD MANUEE. 261 

easy to understand why guano surpasses, in these respects, 
many other manures. 

As regards certamty of action, guano will not bear 
comparison with farm-yard manure, which, from its 
nature, is effective in all cases ; for farm-yard manure 
restores to the land all the soil constituents of the pre- 
ceding rotations, though not in the same proportions, 
whereas guano restores only some of them, and cannot, 
therefore, replace farm-yard manure. As guano, however, 
contains, with the exception of a certain quantity of 
potash, the chief constituents (phosphoric acid and 
ammonia) of the exported corn and flesh, the addition of 
a certain proportion of guano to farm-yard manure may 
serve to restore the proper composition of the latter, and, 
with it, also that of the soil. 

Let us suppose, for the purpose of illustration, that a 
hectare of land has been manured with 800 cwt. of farm- 
yard manure, containing, according to Voelker's analysis, 
272 kilogrammes of phosphate, and that the field has, at 
the end of the rotation, returned the same quantity of 
farm-yard manure of the same composition, and has lost 
by the corn and the animal produce exported, altogether 
135 kilogrammes of phosphates ; the productive power 
of this field, in so far as it depends upon the phosphates, 
would not only remain unaltered, but would even be 
considerably increased, by adding to the 800 cwt. of 
farm-yard manure supplied to it at the commencement 
of a fresh rotation, 400 lbs. of guano (with 34 per cent, 
of phosphates in it). 

Kilogrammes 
The farmyai-d mauiire supplied to the land . . 272 of phosphates 

In the produce exported the field lost . . .135 ,, 

There remained in the arable soil .... 137 „ 
In the new rotation was added by the fresh supply 

of 800 cwt. of farm-yard manure . . . 272 ,, 

By the addition of the 400 lbs. of guano . . 135 ,, 

Altogether ...... 544 „ 



262 GUANO. 

At the beginning of the new rotation the arable soil 
contained, accordingly, twice as much phosphates as at 
the beginning of the preceding one. 

It will thus be seen that, under these circumstances, 
where a field receives back, in the farm-yard manure, a 
larger share of phosphate than it has lost in the crops, 
the action of guano upon it will grow feebler from year 
to year, until at last it ceases to be appreciable. 

But the case is very different as regards the application 
of guano on fields to Avhich a smaller quantity of phos- 
phates is returned in the farm-yard manure than has been 
lost in the crops, and that have, for instance, been culti- 
vated for half a century upon the farm-yard manuring 
system. It has already been explained, that on such fields 
certain constituents of the fodder plants and of straw, 
more particularly soluble silicic acid and potash, are conti- 
nually increasing in the arable soil, whilst by the export 
of corn and flesh its store of mineral substances is re- 
duced by the quantity contained in the exported matters. 
The two sets of constituents had jointly produced the 
crop. By taking away the seed-constituents a corre- 
sponding amount of the straw and fodder constituents 
was, accordingly, rendered ineffective. In fields of this 
description, manuring with guano not only brings up the 
amount of produce to the former standard, but frequently 
even increases it to a surprising extent, when the soil 
contains a large store of other assimilable food elements, 
which require only the presence of the guano consti- 
tuents to make them available for nutrition. In the in- 
creased produce thus obtained, there is, of course, car- 
ried off, together with the guano constituents, also a part 
of the store of the other food elements ; and upon 
repeated manurings with guano the fertilising effect of 
that agent must therefore necessarily become feebler in 



REASON OF THE EFFECTIVE ACTION OF GUANO. 263 

the same proportion as the quantity of these other food 
elements decreases in the gromid. The fertihsing action 
of all compound manures is rarely dependent upon one 
constituent alone ; and as guano contains, in its ammonia 
and phosphoric acid, two food elements, which require 
the presence of each other to be available, manuring with 
guano insures the action of the phosphoric acid, because 
the particles of the latter are in immediate contact with 
ammonia particles, that are at the same time also avail- 
able to the roots ; and in the same way the phosphoric 
acid insures and increases the action of the ammonia. 

In a soil abounding in ammonia, manuring with phos- 
phates alone possessing the same degree of solubility, 
will produce the same effect as guano. 

When ammonia salts fail to produce any effect on a 
field whilst guano is found to act favourably, there is 
reason to attribute the beneficial effect of the guano prin- 
cipally to the phosphoric acid in it ; but in the reverse 
case the conclusion would not hold equally good, because 
the salts of ammonia produce two different kinds of 
effects ; they may, under certain circumstances, consider- 
ably increase the amount of produce, and yet the favour- 
able effect may not be positively attributed to the action 
of ammonia as such (see page 77). 

The presence in the soil of a sufficient quantity of 
potash and silicic acid is always presupposed when guano 
increases the produce of corn ; and on a soil rich in 
potash and magnesia, the application of guano alone 
insures a succession of crops of such plants, which, like 
potatoes, requke for their growth chiefly potash and 
magnesia. 

Meadows and corn fields which gave at first large crops 
with guano, become at last, by the continued use of this 
agent, frequently so drained of silicic acid and potash, as 



264 GUANO. 

to lose for many years their original productiveness. At 
the same time it cannot be denied that there may be 
many soils which, for several years, by the aid of guano 
alone, might be made to produce high cereal crops before 
this state of exhaustion appears ; but it will at last inevi- 
tably come, and it will then be very difficult to repair the 
damage. 

In 800 cwt. of farm-yard manure with which a hectare 
of land is manured in a rotation of crops, the soil 
receives (according to Voelker's analysis) the same quan- 
tity of phosphates and of nitrogen as in 800 kilo- 
grammes (15-7 cwt.) of guano; in other words, there is 
as much of these two elements of food for plants con- 
tained in 1 lb. of the latter agent as in 50 lbs. of farm- 
yard manure. Guano, therefore, contains these elements 
in the most concentrated form, and permits the apph- 
cation of them to certain parts of the field more 
conveniently than by farm-yard manure, as is often 
advantageously done after putting in the seed. In 
many places, guano is mixed with g5rpsum to reduce 
its over-powerful action. The gypsum divides the guano 
particles and causes them to be more equally distributed 
over the field ; but there is no real diminution of the 
chemical action of the ammoniacal salts; the gypsum 
decomposes the oxalate and the phosphate of ammonia 
into sulphate of ammonia, and phosphate and oxalate 
of lime. The phosphate of lime formed in this way 
is in a state of infinitely fine division, in which it is 
most suitable for the roots of plants ; however, a small 
portion only of the phosphoric acid is converted into 
this state, and with the removal of the oxahc acid, ceases, 
also, the beneficial influence which the latter exercises in 
promoting the difiiision of the phosphoric acid. 

It will, therefore, be found much more effective to 



GUANO AND SULPHURIC ACID. 265 

moisten the guano with water to which a little sulphuric 
acid has been added, and to mix it, after twenty-four 
hours, with saw-dust, turf-dust, or mould, instead of 
gypsum, and to strew this mixture over tlie surface of the 
field. The rain water dissolves out the phosphate of 
ammonia, which slowly sinks into the ground, and all 
parts of the soil with which the solution comes in contact 
are enriched at the same time with phosphoric acid 
and ammonia. If to the saw-dust, turf-dust, &c., gypsum 
is added, it decomposes with the phosphate of ammonia 
into very finely-divided phosphate of Hme and sulphate 
of ammonia, which are separated by the rain water ; the 
soluble sulphate of ammonia penetrating deeper into the 
ground and carrying down with it a small qiiantity of 
the phosphate of lime, whilst the main bulk of the latter 
is left on the top. 

On land poor in potash, the addition of wood ashes to 
the guano, moistened with water and sulphuric acid, will 
be found beneficial, as the carbonate of potash decom- 
poses with the phosphate of ammonia into carbonate of 
ammonia and phosphate of potash, and the potash does 
not interfere with the phosphoric acid penetrating into 
the soil. 

The results obtained, in the Saxon experiments, by 
manuring with guano, afford a clear insight into all the 
peculiarities observed in the action of this manuring 
agent. 

If we compare the produce severally obtained by 
manuring with guano and with farm-yard manure (see 
page 190), we are led to the following considerations on 
the condition of the experimental field : — 



266 



GUANO. 

Manuring with guano. 



Quantity of guano applied 


Cunnersdorf 


Miinsegast 


Kbtitz 


Oberbobritzsoh 


lbs. 
379 


lbs. 
411 


lbs. 
411 


lbs. 
616 


1851 
Rye corn 

,, straw . 


1941 
5979 


2693 
5951 


1605 
4745 


2391 

5877 


1852 
Potatoes 


17904 


17821 


19040 


13730 


1853 
Oat corn 
,, straw . 


2041 
2873 


1740 
2223 


1188 
902 


1792 
2251 


1854 
Clover .... 


9280 


6146 


1256 


5044 



Increuse of produce above the unmanured 


plot (see p 


190). 


Amount of nitrogen in 


Cunnersdorf 


Mausegast 
(1853, barley 
instead of oats) 


Kotitz 


Oberbobritzsch 


lbs. 


lbs. 


lbs. 


lbs. 


the manure 


49-3 


53-4 


53-4 


80-1 


Rye corn 


765 


455 


341 


938 


„ straw 


3028 


1369 


1732 


2862 


Potatoes 


1237 


925 


463 


3979 


Oat corn 


22 


451 


151 


264 


„ straw 


310 


383 


455 


439 


Red clover . 


136 


608 


161 


4133 



In Cunnersdorf, the increase of produce obtained in 
1851, over the unmanured field, amounted to — 



Corn 
lbs. 


straw Batto 
lbs. lbs. 


337 


1745 = 1 : 5 


765 


3028 = 1 : 3-8 



By farm-yard manure (180 cwt.) 
By guano (379 lbs ) 

The field at Cunnersdorf was naturally rich in those 
ingredients which we have designated as Qt (straw) con- 
stituents (silicic acid, potash, lime, magnesia, iron), and 



PRODUCE OF MANURED AND UNMANURED FIELDS. 267 

the increase of these by the farm-yard manure augmented 
the straw at the exjDense of the gram crop. The farm- 
yard manure contamed too httle of the K (corn) consti- 
tuents (nitrogen, phosphoric acid). 

This explains the powerful action of guano (which 
contains chiefly K constituents) upon this field ; the 
increase of corn by its means was more than double that 
obtained from farm-yard manure, and a more suitable 
proportion was established between the K and St consti- 
tuents in the ground. 

At Mdusegast the increase of produce obtained in 
1851, above that of the unmanured field, amounted 
to— 





Com 


straw Eatio 




lbs. 


lbs. lbs. 


By farm -yard manure (194 cwt.) 


. 345 


736 = 1 : 2-1 


By guano (41 1 lbs.) 


. 455 


1369=1 : 3-0 



This field was richer in K and St constituents than the 
Cunnersdorf field, and contained, already, an excess of S^ 
constituents. The K constituents supplied in the guano 
constituted a much smaller fraction of the whole store 
ah-eady present in the field than was the case with the 
Cunnersdorf field, and their effect tended rather to 
increase the produce of straw than that of corn. 

The application of guano had the effect of producing 
the same quantity of straw on the Cunnersdorf as on the 
Mausegast field (5951 and 5979 lbs.) ; but the corn reaped 
from the latter exceeded that obtained from the former 
by 752 lbs. The Mausegast field was much richer in K 
constituents than the Cunnersdorf field. 

At Kotitz the increase of produce was — 





Com 


straw Ratio 




lbs. 


lbs. lbs. 


By farm-yard manure (229 cwt.) , 


. 352 


1006 = 1 : 2-8 


By guano (411 lbs.) 


, 341 


1732 = 1: 5 



The effect of guano upon the straw produce was here 



268 GUANO. 

out of all proportion greater than that of farm-yard 
manure, whilst the produce of corn was smaller. It is 
quite evident that one constituent acting more powerfully 
in the direction of the formation of straw was supphed to 
the field in larger proportion in the guano than in the 
farm-yard manure. Experiments with superphosphate 
(excluding ammonia), or with an ammoniacal salt (exclud- 
ing phosphoric acid), would have shown to which of 
these two elements the difference in the produce was 
owing. 

At Oherhohritzsch the increase of produce was — 





Com 


straw Ratio 




lbs. 


lbs. lbs. 


By farm-yard manure (314 cwt.) 


. 452 


913=1 : 2 


By guano (616 lbs.) 


. 938 


2812^1 : 3 



As the quantity of guano used at Oberbobritzsch was 
about 50 per cent, more than in the preceding expe- 
riments, no comparison as to amount can be made 
between the produce of this field and that of the others. 
What is again remarkable here is the similarity of the 
condition of this and the Mausegast field ; on both, farm- 
yard manure gave straw and corn in the proportion of 
1-2 ; guano, in the proportion of 1-3. As regards the 
power of the soluble guano constituents to pass throuo-h 
the -soil, we find from these experiments the same con- 
ditions existing as with those of farm-yard manure. At 
Cunnersdorf and Kotitz the whole guano constituents 
hardly produced any effect upon the clover crop ; whilst 
at Mausegast and Oberbobritzsch a perceptible increase 
was the result. 

Silicic acid, which gives strength and firmness to stalks 
and leaves, is not one of the ingredients of guano ; hence, 
after manuring with guano, the tendency of the cereals to 
lodge, so much dreaded by agriculturists, is observed on 



mCEEASE OF PEODUCE BY GUANO. 



269 



many fields poor in silicic acid, whilst on others abounding 
in this substance it does not occur. On many soils this 
tendency may be cured by dressing with hme before 
applying the guano ; and in other cases it may be les- 
sened by mixing dung made from straw with the guano. 

If we calculate the increase in the produce of cereals, 
potatoes, and clover, obtained severally in the years 1851 
to 1854, from 100 lbs. of guano we find 

100 /5s. of guano gave increase of produce 



1851 and 1853 
Rye and oats 


Cnnnersdorf 


Mausegast 


Kbtitz 


Oberbobritzsch 


lbs. 
1088 


lbs. 
646 


lbs. 
354 


lbs. 
731 


1852 
Potatoes 


326 


225 


112 


646 


1854 
CloTer .... 


36 


172 


39 


670 



These results show that the same quantity of guano has 
an equally dissimilar effect upon difierent fields as farm- 
yard manure, and that it is quite impossible to draw from 
the crops obtained any inference as to the quality or 
quantity of the manuring agent employed to produce 
them. The field at Mausegast had received the same 
amount of guano as the Kotitz field, both, accordingly, 
the same quantity of nitrogen and phosphoric acid ; yet 
in cereals and potatoes the increase of produce was twice 
as great, and in clover much greater in the former than 
in the latter. 

How very httle the crops will enable us to draw com- 
parisons between the effects of the several constituents of 
one and the same manuring agent, may be clearly seen 
from the results of the experiments at Cnnnersdorf and 
Oberbobritzsch. 



270 GUANO. 



At Cunnersdorf, 100 lbs. of guano gave an increase of 
produce in cereals, potatoes, and clover, containing — 

Nitrogen Potash Phosphoric acid Lime 
lbs. lbs. lbs. lbs. 

Increase of produce . 9'2 16'1 3'5 3'6 

The guano contained . 13-0 2-0 12-0 12-0 

More in the manure . 3-8 — 8-5 8*4 less in the crops 

Less in the manure . — 14-1 — — more in the crops 

At Oberbobritzsch, 100 lbs. of guano gave an increase of 
produce, containing — 

Nitrogen Potash Phosphoric acid Lime 
lbs. lbs. lbs. lbs. 

Increase of produce . 23'0 15*5 6"1 16'9 

The guano contained . 13-0 2-0 12-0 12-0 

More in the manure . — — 5*9 — less in the crops 

Less in the manure . 10"0 13"5 — 4-9 more in the crops 

The difference in the effect produced by the guano on 
the two fields is most strikingly exhibited by these tables. 
At Cunnersdorf the produce reaped contained 30 per 
cent, less, at Oberbobritzsch 77 per cent, more nitrogen 
than the manure applied. 



271 



CHAPTEE VII. 

POUDKETTE HUMAN EXCEEMENTS. 

Poudrette, nature of ; small amount of the food of plants in it — Human 
excrement, its value — Construction of the privies in the barracks at 
Rastadt — Calculation of the amount of corn produced by the exci-ement 
collected ; importance to the neighbourhood — Its effect not impaired by 
deodorising with sulphate of iron — The excrement of the inhabitants of 
towns as manure — Its importance. 

POUDEETTE, sold as manure, sbould consist simply 
of tlie desiccated excrements of man made into a 
transportable form. This is not the case, however, as 
most poudrettes contain, in reahty, only a comparatively 
smaU proportion of excrementitious matter. To show 
this, it will suffice to point out that the poudrette of 
Montfaucon, which is one of the best sorts, contains 
28 per cent., that of Dresden from 43 to 56 per cent,, 
that of Frankfort above 50 per cent., of sand. No kind 
of poudrette is ever met with in commerce containing 
more than 3 per cent, of phosphoric acid, and the same 
amount of ammonia. The construction of privies in 
dwelling-houses (at least, in Germany) does not make it 
practicable to keep out the sweepings and other rubbish 
of the house ; besides, when emptying the pits, it is 
often the practice, after taking out the fluid contents, to 
throw into the residuary mass some solid porous body, 
such as brown-coal or turf-dust, to make it drier and 
more convenient for removal. All additions of the kind, 
of course, diminish the percentage of effective and 



272 POUDEETTE — HUMAN EXCEEMENTS. 

available food elements, and increase the costs of transport. 
The privy pits, moreover, are but rarely water-tight, and 
permit the greater part of the urine and other fluid 
contents to leak away, thus causing the loss of a good 
deal of the most valuable matter, such as the potash 
salts, and the soluble phosphates. The following state- 
ment will show the great value of the excrement of 
man. In the fortress of Kastadt and in the soldiers' 
barracks in Baden generally, the privies are so con- 
structed that the seats open, through wide funnels, into 
casks fixed upon carts. By this means the whole of the 
excrements, both fluid and solid, are collected without 
the least loss. When the casks are full, they are replaced 
by empty ones.* 

The food of the soldier, in Baden, consists chiefly of 
bread, but also of certain daily rations of meat and vege- 
tables. As the body of an adult does not increase in 
weight, it needs no particular calculation to make out 
that the collected excrements must contain the ash-con- 
stituents of the bread, meat, and vegetables, and also the 
whole of the nitrogen of the food. 

To produce a pound of corn, the soil has to furnish 
the ash-constituents of that pound of corn ; if we supply 



* The price of a cart is from 100 to 125 florins =r £8 6s. 8d. to ^10 8s. M. 
It will last about five years. The original outlay incurred by the 
Army administration in Baden, in 1856 and 1857, for the carts and" 
casks amounting to about ^370, was sjDcedily repaid out of the proceeds 
of the manure. 

The collective number of the garrisons of Constance, Freiburg, 
Eastadt, Carlsruhe, Bruchsal, and Mannheim, averages about 8000 men. 
The receipts for manure sold were in 1852, £285 ; in 1853, £315 ; in 
1854, £443; 1825, £400; 1856, £668; 1857, £668 ; 1858, £680 ; 
£50 or £60 are to be deducted fi-om these receipts annually for cost 
of maintenance, repair, &c., of the carts, &c. (' Journ. of the Agric. 
Soc. of Bavaria,' April 1860. Page 180.) 



HUMAN EXCEEMENTS FEOM RASTADT. 273 

these ash-constituents to a suitable field, the latter will 
thereby be enabled to produce, in a number of years, 
one pound of corn more than it would have done 
without this additional supply of ash-constituents. The 
daily ration of a soldier, in Baden, is 2 lbs. of bread ; 
the excrements of the 8000 men of the different garrisons 
contain accordingly, per day, the ash-constituents and the 
nitrogen of 16,000 lbs. of bread, which returned to the 
soil will fully suffice to reproduce the same quantity 
of corn as had been used, in form of flour, to bake 
the 16,000 lbs, of bread. Eeckoning l:^lb. of corn to 
2 lbs. of bread, the excrements of the soldiers in the 
Grand Duchy of Baden give, therefore, annually, the ash- 
constituents required for the production of 43,760 cwts. 
of corn. 

The peasants about Eastadt and the other garrison 
towns, having found out at last by experience the power- 
ful fertilising effect of these excrements upon their 
fields, now pay for every full cask a certain sum (still 
rising in price every year), which not only has long since 
repaid the original outlay, besides covering the annual 
cost of maintenance, repairs, &c., but actually leaves 
a handsome profit to the department. 

The results brought about in these districts are highly 
interesting. Sandy wastes, more particularly in the 
vicinity of Eastadt and Carlsruhe, have been turned into 
smihng corn-fields of great fertility. Assuming, for the 
sake of illustration, that the peasants had to furnish the 
whole of the corn produced by means of this manure, 
to the miHtary administrations of the several garrison 
towns, there would thus be established a perfect circula- 
tion of these conditions of life, wliich would provide 
8000 men with bread, year after year, without in the 
least reducing the productiveness of the fields on which 



274 POUDRETTE — HUMAN EXCREMENTS. 

the corn is gro^vii, because the conditions required for 
the production of corn being thus always returned to the 
soil, would continue to circulate and yet always remain 
the same.* 

What is said here about the corn-constituents apphes, 
of course, equally to the constituents of meat and vege- 
tables, which, returned to the field, will reproduce as 
much meat and vegetable matter as has been consumed. 
The same relation that exists between the inhabitants of 
the barracks in Baden and the fields supplying them with 
bread, exists equally between the inhabitants of towns 
and the country around. If it were practicable to col- 
lect, without the least loss, all the solid and fluid excre- 
ments of all the inhabitants of towns, and to return to 
each farmer the portion arising from the produce 
originally supplied by him to the town, the productive- 
ness of his land might be maintained almost unimpaired 
for ages to come, and the existing store of mineral 
elements in every fertile field would be amply sufficient 
for the wants of the increasing populations. At any 
rate, that store is, at present, still sufficient to do so, 
although the number of farmers who take care to cover 
by an adequate supply of suitable manures the loss of 
mineral matters sustained by the land in the crops grown 
on it, is but small in proportion to the whole agricul- 
tural population. However, sooner or later, the time 
will come when the deficiency in the store of these 

* Wlien, some years ago, an order was suddenly issued by tlie 
authorities of the city of Carlsrulie, to deodorise and disinfect the pits 
and cesspools with sulphate of iron, before being emptied, the farmers 
refused at first to pay any longer for the contents, which they argued were 
by this treatment deprived of their fertilising virtue. Experience has 
shown that this is not the case, and the disinfected dung commands as 
high a price now as the article in its pure state did formerly. The dung 
in the privy carts requires no disinfecting. 



LOSS OF MANURE BY CAEELESSNESS. 275 

mineral matters will be important enough in the eyes of 
those who are, at present, so void of sense as to believe 
that the great natural law of restoration does not apply to 
their own fields ; and the sins of the fathers, in this 
respect, will also be visited upon their posterity. In 
matters of this kind, inveterate evil habits are but too 
apt to obscure our better judgment. Even the most 
ignorant peasant is quite aware that the rain fahing 
upon his dung-heap washes away a great many silver 
dollars, and that it would be much more profitable to 
him to have on his fields what now poisons the air of his 
house and the streets of his village ; but he looks on un- 
concerned, and leaves matters to take their course, because 
they have always gone on in the same way. 



T 2 



276 



CHAPTER VIIL 

EAETHY PHOSPHATES. 

Pligh agricultural value of phosphates — Phosphates of commerce ; selection 
of the kind to be used dependent on the object in view, and on the nature 
of the soil — The rapidity and the duration of the effect of the neutral 
and of the soluble phosphate (superphosphate) of lime — The Saxon 
maniu'ing experiments. 

THE earthy phosphates are among the most important 
agents for restoring the impaired productiveness of 
land ; not that tliey influence vegetation in a more marked 
manner than other mineral elements, but because the 
system of cultivation pursued by the corn and flesh pro- 
ducing farmer tends to remove them from the soil in 
larger proportion than other constituents. 

In choosing among the phosphates of commerce, the 
farmer should always keep in view the object which he 
intends to accomphsh, as some sorts will answer better 
for certain purposes than others. 

The so-called superphosphates are commonly phos- 
phates to which a certain quantity of sulphuric acid 
has been added, to convert the insoluble neutral lime 
salt into a soluble acid salt. When mixed with a salt 
of ammonia and a salt of potash, they are often called 
guano or ammoniacal superphosphates. A good super- 
phosphate generally contains from 10 to 12 per cent, of 
soluble phosphoric acid. On land poor in clay and lime 
the superphosphates are particularly suitable for supply- 
ing the upper layer of the soil with phosphoric acid. 



PROPEETIES OF BONE-DUST. 277 

Their effect upon the produce of potatoes and of cereals 
on such fields is equal to that of Peruvian guano. For 
turnips and rape, which derive advantage from the pre- 
sence of sulphuric acid, they have a special value. 
On chalky soils, the free phosphoric and sulphuric acids 
are immediately neutralised, by which they are deprived 
of one of their essential properties, viz., their ready 
diffusibihty, which renders them so valuable a manure 
for other soils. 

Among the neutral phosphates bone-dust holds the first 
rank. When bones are exposed, under high pressure, to 
the action of steam, they lose their toughness, and swell 
up into a soft gelatinous mass, which, after drying, may 
be readily ground to a fine powder. In this form it 
spreads, with great rapidity, through the soil ; it dissolves 
in water to a small but perceptible extent, without requir- 
ing the presence of any other solvent. What dissolves, 
under these circumstances, in water, is a combination of 
gelatine with phosphate of hme, which is not decomposed 
by the arable earth, and therefore penetrates deep into 
the ground — a property wanting in the superphosphate. In 
the moist ground, however, the gelatine speedily putrefies, 
being converted into ammonia compounds, and the phos- 
phate of lime is then retained by the arable earth. Bone- 
dust is the agent best adapted to supply phosphate of 
lime to the deeper layers of the arable soil, for which 
purpose the superphosphates are not suitable. Bone- 
earth, or bone-ash, is the name applied to bones freed, by 
calcination, from the glue or gelatinous part. The animal 
charcoal of sugar refineries belongs to this category. 
It must be reduced to the finest powder to render 
it fully available for manuring purposes. To effect 
its more speedy distribution through the soil, the pre- 
sence of a decaying organic substance is necessary to 



278 EAETHY PHOSPHATES. 

supply the carbonic acid required for its solution in rain 
water. An excellent way is to mix the powder with 
farm-yard manure and let the mixture ferment. Among 
the phosphates of commerce, the guano coming from the 
Baker and Jarvis Islands are distinguished, before others, 
by their acid reaction and greater solubility. They con- 
tain only a small quantity of an azotised substance, no uric 
acid, and small proportions of nitric acid, potash, mag- 
nesia, and ammonia. The Baker guano contains as much 
as 80 per cent., the Jarvis guano 33 or 34 per cent, of 
phosphate of lime ; the latter having, besides, 44 per 
cent, of gypsum. In diffusibihty, these guanos, when 
equally finely powdered, approach nearest to bone-dust : 
their condition also enables the farmer who wishes 
to accelerate their action, to convert them most readily 
into superphosphates (100 parts by weight of Baker 
guano require 20 to 25 per cent, of concentrated, or 30 
to 40 per cent, of the lead chamber sulphuric acid). 

The influence of these neutral phosphates upon the pro- 
duce of a field is generally less marked in the first than 
in the following years, as it takes a certain time to effect 
their diffusion through the soil. The speedier or sloAver 
manifestation of their action upon a field depends, in a 
great measure, upon the state of fineness of the powder 
to which they have been reduced, the greater or less 
porosity of the soil, the presence in it of decaying mat- 
ters, and careful tillage ; but, under any circumstances, 
they require a certain store of soluble silicic acid, and of 
soda and potash in the soil. 

The subjoined table giving the produce obtained, in the 
years 1847-50, by H. Zenker, at Kleinwolmsdorf, in 
Saxony, shows the difference between guano and bone- 
dust as regards rapidity and duration of action. In the 
first year the guano gave the larger produce, which 



PEODUCE FKOM GUANO AND BONE-DUST. 



279 



became smaller in each following year ; in tlie first year 
the crop from the bone-dust was smaller, but in the suc- 
ceeding years the increase was most remarkable. 



1847 
Winter corn . 


Bone-dust (822 lbs.) 


Guano (411 lbs.) 


Corn 


Straw 


Corn 


Straw 


lbs. 
2798 


lbs. 
4831 


lbs. 
2951 


lbs. 

4711 


1848 
Barley .... 


2862 


3510 


2484 


3201 


1849 

Vetches 


1591 


5697 


1095 


4450 


1850 
Winter corn . 


1351 


2768 


732 


2481 



The 411 lbs. guano contained 53, and the total produce 
271 lbs. of nitrogen, or very nearly five times more. 
The bone-dust contained 37 lbs. of nitrogen, whereas in the 
total produce there were 342 lbs.,or nearly nine times more. 
The bone-dust gave in the crops altogether 71 lbs. of 
nitrogen more than the guano. Between the quantity of 
nitrogen in the manure and the amount of the crops 
reaped, there is, therefore, no connection whatever. 

In the Saxon experiments, the plots manm-ed with 
bone-dust gave the following results : — 

Manuring with bone dust. 



Quantity of bone-dust used 


Cunnersdorf 


Kbtitz 


Oberbobritzscb 


Mausegast 


lbs. 
823 


lbs. 
1233 


lbs. 
1644 


lbs. 
892 


1851 
Eye corn 
„ straw 


1399 

4167 


1429 

3707 


2230 
5036 


1982 
4365 


1852 

Potatoes 


18250 


19511 


11488 


19483 


1853 
Oat corn 
,, straw 


2346 
3105 


1108 
1224 


1718 
1969 


1405 
1905 


1854 
Clover .... 


10393 


2186 


7145 


5639 



280 EARTHY PHOSPHATES. 

Increase of produce over the unmanured field (see page 190). 



1851 
Rye corn 

,, straw . . ; 


Curmersdorf 


Kbtitz 


Oberbobritzscli 


Mausegast 
(1853, barley 
instead of oats) 


lbs. 

227 
1216 


lbs. 

165 
694 


lbs. 

777 
2021 


lbs. 


1852 
Potatoes 


1583 


934 


1737 


2587 


1853 
Oat corn 
„ straw . 


327 
542 


— 


190 
157 


116 
65 


1854 
Clover .... 


1249 


1091 


6234 


101 



The field at Kotitz got 50 per cent, more bone-dust 
than the Cunnersdorf field ; yet its produce of all the 
crops was lower than that of the latter. The field at 
Oberbobritzsch got, m 1851, twice the quantity of manure 
that was apphed to the Cunnersdorf field ; the result 
was, in the first year, an increase of corn of 250 per 
cent., and of straw of 66 per cent, more on the former 
than on the latter. In the third year, however, the 
increase of produce of oats, both in grain and straw, 
was considerably larger at Cunnersdorf than at Ober- 
bobritzsch. 

The most curious part of the results is the great diSer- 
ence in the increase of the produce of clover on the 
several fields ; from the field at Oberbobritzsch nearly 
six times as much clover was obtained as from that at 
Kotitz, although the former had received only one-fourth 
more bone-dust than the latter. 

A glance at the table shows that in the experiments at 
Cunnersdorf, Kotitz, and Oberbobritzsch, the quantities 
of bone-dust severally applied as manure were as 
1 : IJ : 2. A comparison of the increase of produce 



INCEEASE OF PEODUCE FEOM BOIv^E-DUST. 



281 



obtained by bone-earth, just as in the case of guano and 
farm-yard manure, again demonstrates that there is no 
connection or relation of dependence between the amount 
of manure and the increase of the crops. 



100 lbs. bone-dust 


gave increasi 


' of produce 




1851 and 1853 
Eye and oats .... 


Ciumersdorf 


Kbtitz 


Oberbobritzsch 


lbs. 
280-8 


lbs. 
40-1 


lbs. 
191 


1852 
Potatoes 


192 


75 


105 


1854 
Clover 


152 


96 


380 



282 



CHAPTEE IX. 

GKOUND EAPE-CAKE. 

Nature and composition of; the difFiisibility of its constituents in tlie soil is 
comparatively great — Its importance as a manuring agent is small — 
The Saxon agricultural experiments with rape-cake — The inferences from 
them. 

THE residuary mass left by rape-seed after the extrac- 
tion of the fatty oil from it by the press, contains a 
large proportion of a matter abounding in nitrogen, 
which is nearly related to the casein in milk. In addi- 
tion to this substance, it contains the same incombustible 
or ash-constituents as the ashes of seeds. The rape-seed 
ash consists of phosphates, and differs but little in com- 
position from the ash of the grain of rye ; phosphates of 
the alkahes and phosphate of magnesia predominate in it. 
There is no great error made in assuming that in 100 lbs. 
of rape-cake a field receives the same amount of the 
incombustible constituents of rye grain as is contained in 
250 to 300 lbs. of the latter. 

The azotised matter in rape-cake powder is shghtly 
soluble in water, but its solubility increases with inci- 
pient putrefaction ; hence the nutritive matters contained 
in it are much more widely diffused in the ground than, 
for instance, the principal ingredients of guano, ammonia, 
and phosphoric acid, which are absorbed, as soon as dis- 
solved, by the earth particles that come in contact with 
them. Whereas with rape-cake powder this takes place 



EAPE-CAKE AS A MANUEE. 



283 



only after its azotisecl matter has been completely decom- 
posed, and its nitrogen converted into ammonia. This 
decomposition proceeds, however, pretty fast, and the 
effect of rape-cake makes itself felt, accordingly, m the 
very first year of its application. 

It is owing to this greater diffusibihty of its consti- 
tuents in the earth that rape-cake appears to exercise a 
somewhat more powerful effect upon vegetation than guano, 
for instance, with an equal amount of phosphoric acid. 

However, rape-cake holds no very important rank as a 
manure, simply because very few agriculturists are in a 
position to procure any considerable quantity of it for 
manuring purposes. Besides, when its great value as an 
article of food for cattle shall be more universaUy known 
and acknowledged, the increasing price will restrict, stiU 
more, its use as a manuring agent ; the more so since the 
excrements of animals fed upon rape-cake contain the 
principal bulk of the constituents to which is due its 
efficacy as a fertilising agent. 

The following results were obtained, in the Saxon expe- 
riments, by manuring with ground rape-cake : — 



Manure 


Cunnersdorf 


Miiiisegast 


Kotitz 


Oberbobritzsch 


lbs. 
1614 


lbs. 
1855 


lbs. 
1849 


lbs. 
3288 


1851 
Eye corn 

„ straw . 


1868 
5699 


2645 
6998 


1578 
4218 


1946 ■ 

4475 


1852 

Potatoes 


17374 


18997 


19165 


10442 


1853 
Oat corn 
„ straw . 


2052 
2768 


barley 
1619 
2298 


1408 
1550 


1517 
1939 


1854 
Clover .... 


9143 


6659 


981 


2105 



284 GROUND RAPE-CAKE. 

Increase of produce over the umnanured field (see p. 190). 



Amount of nitrogen in 
manure 


Cmmersdorf 


Mausegast 


Kotitz 


Oberbobritzsch 


lbs. 
78-9 


lbs. 
88-8 


lbs. 
89 


lbs. 
157-8 


1851 
Eye corn 
„ straw . 


692 

2748 


407 
1416 


314 
1205 


493 
1460 


1852 
Potatoes 


707 


2101 


588 


691 


1853 
Oat corn 
„ straw . 


33 

205 


330 

458 


69 
193 


127 


1854 
Clover-liay . 




1121 


— 


1194 



Here, again, we see, as in the case of farm-yard 
manure, guano, and bone-dust, that on no one field did 
the effect of the rape-cake bear any visible proportion or 
relation to the quantity used. 

1000 lbs. of ground rape-cake gave increase of produce 



1851 
Eye corn and straw 


Cunnersdori 


Mausegast 


Kotitz 


Oberbobritzscli 


lbs. 
2130 


lbs. 
989 


lbs. 
820 


lbs. 
594 


1853 
Oat corn and straw 


147 


424 


141 


39 


1852 
Potatoes 


438 


1132 


318 


210 


1854 
Clover-hay . 


— 


604 


— 


332 



These experiments are interesting in reference to the 
effect of the nitrogen supphed in the manure. A com- 
parison of the increase of produce obtained at Ober- 
bobritzsch, severally by guano and ground rape-cake, 
gives the following result in this respect : — 



EFFECT OF THE NITROGEN IN THE MANUEE. 285 



Oberhobritzsch. 

611 lbs. guano 3288 lbs. ground rape cake 
=80 lbs. nitrogen =157-8 lbs nitrogen 

and 74 lbs. and 39-5 lbs. 

phosphoric acid phosphoric acid 

1851 and 1853. Rye and oats . 4503 lbs. 2069 lbs. 

1852. Potatoes . . . 3979 „ 691 „ 

1854. Clover-hay . . . 4133 „ 1194 „ 

The one field at Oberhobritzsch received in the ground 
rape-cake nearly double the quantity of nitrogen that the 
other got in the guano, and the difference in the produce 
of the two is in the highest degree striking. 
In the two experiments — 



The nitrogen in the manures was as 


In the 
guano 

1 - 


In the 
rape-cake 

: 2 


In the produce it was : 

„ cereals, as .... 


2 


: 1 


„ potatoes, as ... . 
,, clover, as .... 


5-7 
3-4 


: 1 
: 1 



The effect of the nitrogen in the guano was, accordingly, 
in the cereals four times, in the potatoes twelve times, 
and in the clover seven times, greater than that of the 
nitrogen in the rape-cake. 

Upon comparing the increase of produce with the 
amount of phosphoric acid m the two manures, we find 
that this increase appears to bear some proportion, though 
yet by no means a definite one, to the amount of phos- 
phoric acid severally contained in them. 

The general results of the experiments made, in a four 
years' rotation, on four different fields at Cunnersdorf, 
Mausegast, Kotitz, and Oberbobritzsch, may be summed 
up as follows : — 

The 48 harvests from the unmanured plots and from 
those manured severally with bone-dust, guano, and 
ground rape-cake, gave in rye grain and straw, in potatoes, 
in oats grain and straw, and in clover, by manuring with — 



266 GEOUND RAPE-CAKE. 



Bone-dust G-uano Gromid rape-cake 

lbs. lbs. lbs. 



Total amount of nitrogen in crops . 1170 1139 1046 

Total amount of nitrogen in crops 

from unmanured plots . . 910 910 910 



Increase of nitrogen over the un- 








manured plots 


260 


229 


136 


The manure contained nitrogen 


207 


236 


415 



More than in manure ... 53 less 7 less 279 

The manure poorest in nitrogen (the bone-dust) 
thus actually gave the highest, and the one richest in 
nitrogen (the rape-cake) the lowest, amount of that 
element in the produce. 

To 100 lbs. nitrogen in the manure, there was obtained 
of that element in the increased produce — 

By bone-dust ...... 125 lbs. 

,, guano . . . . . . . 97 ,, 

,, rape cake . . . . . . 32 ,, 

The amount of phosphoric acid in the crops was 
from — 

Bone-dust Guano Ground rape-cake TJnmanural 

lbs. lbs. lbs. lbs. 

Phosphoric acid . 361 362 338 292 

The manure contained 1102 288 86 — 

The fields gained . 741 — — — 

The fields lost . . — 74 252 292 



2s: 



CHAPTEE X. 

WOOD-ASH. 

The amount of tlie food of plants in it — Box-wood ash gives only the half 
of its potash readily to water — Convenience in mixing- wood-ash with 
earth before applying it — Lixiviated ash, its value — Proper mode of 
applying ashes as a manure. 

IT lias already been stated that the proportion of potash 
is very dissimilar in different wood ashes ; those 
from hard wood being generally richer in that substance 
than those from soft wood. The ash of beech-wood 
gives up to water the one-half of the potash in it, in the 
form of carbonate of potash, the other half remaining in 
combination with carbonate of hme, in a compound which 
is only very slowly decomposed by cold water. The ash 
of pine-wood generally contains, like tobacco ash, a 
larger proportion of lime, so that cold water often seems 
to fail altogether in dissolving any carbonate of potash 
out of it. However, the continued action of water suc- 
ceeds always in gradually extracting from all these ashes 
the whole of the potash ; and since they can be easily 
ploughed deeply in, they are suited better than all other 
potash compounds to enrich mth that alkaH the deeper 
layers of the arable soil. With wood-ashes that part 
readily with their potash to water, it will be found useful 
to mix the ash, before applying it, with an earth that 
absorbs potash, adding so much of the latter that water 
poured upon the mixture will no longer turn reddened 



288 WOOD-ASH. 

litmus-paper blue. This operation of mixing can best 
be performed on the field itself. 

Wood-ash which has been extracted with w^ater, such, 
for instance, as the residue left in the preparation of 
potash, possesses for many fields a high value as a ma- 
nuring agent, not only on account of the potash always 
present in it, but also of the phosphate of hme and soluble 
silicic acid it contains. 

As the upper layers of our corn-fields contain already 
naturally an excess of potash, in proportion to the other 
food elements, ash-manuring, when confined to the 
surface soil, rarely exercises a lasting effect ; but where 
the ash is carried down to the proper depth, it affords an 
excellent means of obtaining permanent crops of clover, 
turnips, or even potatoes. Intelligent manufacturers of 
beetroot sugar use with great success the residuary 
matter from the distillation of their molasses, which con- 
tains all the potash-salts of the beetroot, for maniuing 
their fields, to restore to them the potash removed in the 
beetroot-crops. 



289 



CHAPTEE XI 

AMMONIA AND NITKIC ACID. 

Soiu'ce of tlie nitrogen of plants — Amount of ammonia and nitric acid in 
rain and dew : Bineau, Boussingault, Knop — Quantity of ammonia in the 
air — Quantity of nitrogenous food brought to the soil yearly by rain and 
dew ; more present in the soU than is removed by the crops — The 
general reason for decrease of productive power in soils — Classification 
of manures according to the amoimt of nitrogen; assimilable and spar- 
ingly assimilable nitrogen ; the nitrogen theory; only ammonia according 
to this theory is wanting ; resemblance to the humus theory — Manuring 
experiments with compomids of ammonia by Schattenmann, by Lawes 
and Gilbert, by the Agricultural Union of Munich, and by Kuhlmann — 
The efficacy of a manure is not in proportion to its amount of nitrogen : 
experiments — Large amount of nitrogen in soils ; the experiments of 
Schmid and Pierre ; the arable surface soil contains most nitrogen — 
Form of the ammonia in the soil ; Mayer's experiments — Comportment 
of soil and farm-yard manure with the alkalies — The ineiiective nitrogen 
of the soil made effective by the supply of ash-constituents that are 
wanting — Progress in agriculture impossible if dependent on a supply 
of ammoniacal compounds; results of Lawes' experiments with salts of 
ammonia — The artificial supply of ammonical manures contrasted with 
the crops produced and the increase of population — Increase of nitro- 
genous food by natural means ; formation of nitrite of ammonia by oxi- 
dation in the air according to Schonbeim — Supply of food in excess neces- 
sary to produce corn-crops ; reasons — How the necessary excess of nitro- 
genous food for corn may be obtained from natural sources — The supply 
of nitrogen in farm-yard manure in the Saxon experiments corresponded 
to the crop of clover-hay — Loss of nitrogen in lime soils by oxidation ; 
utility of a supply of nitrogen to such soils — Effect of nitrogenous food 
on the aspect of yoimg plants ; on potatoes — Empirical and rational 
systems of agriculture. 

FEOM the results of a series of most careful observa- 
tions extending over a number of years made by 
Bineau in different parts of France on the amount of 
ammonia and nitric acid in rain water, it appears that 
there fell annually upon the area of a hectare (^2^ acres) 
27 kilogrammes (=59 lbs.) of ammonia (=22 kilo. =48 lbs. 

u 



290 AMMONIA AND NITEIC ACID. 

nitrogen), and 34 kilogrammes (=75 lbs.) of nitric acid 
(=5 kilo. =11 lbs. nitrogen) ; altogether, therefore, 
27 kilo, or 54 ZoUv. lbs. (=59 lbs. Eng.) of nitrogen. 

For an English acre this makes 21-9 ZoUv. lbs. 
( = 24 lbs. Eng.), and for a Saxon acre 30 ZoUv. lbs. 
These numbers nearly coincide with the observations of 
Boussingault and Knop. 

The yearly average quantity of rain falling in various 
districts, according to the position and elevation of the 
locahties, is very unequal ; and investigations have shown 
that the amount of ammonia and nitric acid contained in 
rain-water bears an inverse proportion to the quantity of 
rain. In districts where the rain falls more seldom or 
less in quantity, the water is richer in these constituents 
than in more rainy districts. According to Boussingault, 
dew is richest in ammonia ; according to Knop, not 
richer than rain-water. (See his valuable memoir in the 
8 hefte der ' Landw. Versuchstat. in Sachsen.') But plants 
receive ammonia and nitric acid not merely by means of 
rain-water derived from the ground and in dew, but also 
directly from the atmosphere. The experiments of 
Boussingault (' Annal. de Chem. etdePhys.,' 3 ser. t. liii.) 
leave no doubt whatever with regard to the constant 
presence of ammonia, in the air. In a kilogramme of 
the following substances heated to redness, he found 
these quantities of ammonia, after three days' exposure 
to the air upon porcelain plates : — 



In 1 kilo, quartz-sand *. 


. 0'60 milligr. ammonia 


„ 1 ,, bone-asla 


• 0-47 


,,1 ,, charcoal . 


• 2-9 



Although we can estimate with tolerable certainty the 
quantity of ammonia and nitric acid wdiicli a field 
annually receives in rain-water, yet the determination 
of the same in the dew which moistens plants is not 
practicable. Just as little can we discover how much 



AMMONIA CONVEYED IN EAIN AND DEW. 



291 



ammonia or nitric acid is received by plants directly from 
tlie air, simultaneously with carbonic acid. 

In the elevated plateaus of Central America, where it 
scarcely ever rains, the cultivated and wild plants receive 
their nitrogenous food only from the dew or directly 
from the au* ; and we may assume, without risk of error, 
that the plants which grow in the cultivated fields of 
Europe have as much ammonia and nitric acid furnished 
to them by the air and the dew, as is conveyed to them 
in rain-water. A sandy plain, where no plants grow, 
receives from the rain as much ammonia and nitric acid 
as a cultivated field ; but the latter derives a greater 
quantity through the plants, and more from the leafy 
plants, than from those which are poor in leaves. Let 
us assume that in the Saxon experiments the cereal 
plants, potatoes, and clover, raised upon the unmanured 
land, derived the whole of thek nitrogen from the 
ground, and that nitrogenous food had not been received 
either from the air or from the dew ; then the profit and 
loss of the field in nitrogenous nutriment (according to 
the assumptions made p. 228, that -^ of the nitrogenous 
constituents in clover and potatoes were carried ofi" in 
the form of cattle), may be thus represented : — 

The field at Cunnersdorf. 







Produced 


Lost by 


Gained by 






altogether 


crop sold 


rain 


1851 


lbs. 


Nitrogen 


Nitrogen 


Nitrogen 


lbs. 


lbs. 


lbs. 


Rye corn 


1176 


22-4 


22-4 




„ straw . 


2951 


10-6 


— 




1852 










Potatoes 


16667 


69-8 


6-9 




1853 










Oat corn 


2019 


30-9 


30-0 




„ straw . 


2563 ' 


6-6 


— 




1854 










Clover-hay . , 


9144 


202-1 


20-2 


120 


79-5 


At the beginning of the 


ifth year the 


field was therefore richer, 




in nitrogen, by 




• 


40-5 



u 2 



292 



AMMONIA AND NITRIC ACID. 

The field at Mdusegast. 



1851 
Eye 

1852 
Potatoes 

1853 
Barley ...... 

1854 
Clover-hay ...... 

In 1855 the field was richer in nitrogen by 



Lost by crop sold 
Nitrogen 



lbs. 
427 



7 

22-2 

12-2 
84-1 



G-ained by rain 
Nitrogen 



120 
35-9 



It is hardly necessary to carry this calculation any 
further ; for all give the same result, viz. that even on the 
most unfavourable su|)position, a field receives back, by 
the rain alone, actually more, certainly not less, nitrogenous 
nutriment, than it loses in the ordinary course of agri- 
culture. 

This fact may well justify the assertion that a farmer 
need trouble himself as little about a compensating 
supply of nitrogen, as of carbon. Both are, in fact, 
originally constituents of the air, or capable of again 
becoming air constituents, and are in the circulation of 
life inseparable from one another. 

From the presence of ammonia and nitric acid in rain- 
water we are led to infer that a source of nitrogen exists, 
which without the aid of man, supplies plants with this 
necessary nutriment. With regard to the other nutritive 
substances, such as phosphoric acid and potash, which of 
themselves are not moveable, this restoration from natural 
sources does not exist. Hence, we might have supposed, 
that when inquiry was made as to the causes which, in 
consequence of cultivation, diminish the productive power 
of land, the reason of such decrease would first and 



PEECONCEIVED NOTIONS. 293 

chiefly have been sought in those nutritive substances 
which are of themselves immovable, and not in those 
which possess the power of circulation ; especially when 
it was ascertained that part at least of the latter sponta- 
neously came back to the field every year. But at every 
stage in the developement of a science, preconceived 
ideas will for a time assert their sway ; and such is the 
case with those notions which ascribe to nitrogen a pre- 
eminent importance in the cultivation of land. 

In the consideration of a natural phenomenon, and in 
the investigation of its causes, we cannot tell at first 
whether it be simple or compound ; whether it be due to 
one or to several causes ; hence we are led to attribute 
the results to those alone which 2iTQ first discovered in ope- 
ration. No long time ago, people beheved that all the con- 
ditions of growth lay in the seed alone ; then they found 
that water, and next that the ah% had a very decided 
influence; bye-and-bye they ascribed to certain organic 
remains in the ground, a most important part in the 
fertility of the soil. When at length they discovered 
that, among all the substances used for manure, the 
excrements of animals and the parts and constituents of 
animals, surpassed all the rest in operative power ; wlien, 
too, chemical analysis had shown that nitrogen was the 
chief element in these substances, it is not surprising 
that nitrogen was then esteemed the sole, and afterwards 
the principal, agent in manure. 

This process of reasoning is in accordance with nature, 
and cannot be found fault with. At that time, it was not 
known that the ash constituents of plants, potash, lime, 
and phosphoric acid, play as important a part as nitrogen 
in the vital processes of plants ; nay, not even an idea 
had been formed of the manner in which the nitrogen of 
nitrogenous compounds operates. Men simply held by 



294 AMMONIA AND NITEIC ACID. 

the fact tliat horn, claws, blood, bones, urine, the solid 
excrements of animals and men, exerted a favourable 
influence ; while woody substances, sawdust and similar 
materials, had no effect, or as good as none. If in the one 
case the presence of nitrogen was the reason of activity, 
so in the other case the want of nitrogen caused the want 
of activity ; in short, by the operation of nitrogen all 
facts seemed to be harmonised and explained. 

If the nitrogenous manures depended for their activity 
upon the nitrogen which they contained, it followed 
necessarily that all of them could not possess the same 
value for the farmer, because they did not all contain the 
same amount of nitrogen ; those which had more of this 
substance were manifestly more valuable than those which 
had less. The amount of nitrogen was easily determined 
by chemical analysis ; hence arose the idea to draw up 
for the benefit of farmers a list of manures with a figure 
attached to each showing its relative value ; those which 
were most abundant in nitrogen were considered the 
most valuable, and stood highest in the list. 

In this valuation no importance was attached to the 
form which nitrogen assumed in the various manures, and 
just as little to the substances which were present along 
with the nitrogenous compound. In this list it was quite 
immaterial whether the nitrogenous combination was in 
the form of gelatine, horn, or albumen ; or whether these 
substances were or were not accompanied by earthy or 
alkahne phosphates. Dried blood, claws, horn shavings, 
woollen rags, bones, rape-cake meal, all figured in one and 
the same list. 

As no definite combination was understood by the 
word ' nitrogen,' it was impossible to prove that the 
operation of nitrogenous manures bore any proportion to 
the amount of nitrogen which they contained. 



THE NITROGEN THEORY. 295 

The introduction and application of Peruvian guano and 
nitrate of soda afforded the so-called nitrogen theory 
a foundation to rest upon ; no manure could be com- 
pared with guano for abundance of nitrogen, while it 
surpassed all others in the rapidity and strength of its 
action. The powerful effect produced by it coincided 
entirely with the nitrogen theory ; it corresponded with 
the high amount of nitrogen in the manure, and chemical 
analysis furnished satisfactory conclusions with regard to 
the rapidity of its action. The fact that the influence of 
guano in increasing the crops was generally more rapid 
than that of other manures containing an equal amount 
of nitrogen, made it evident that some one of its consti- 
tuents possessed a peculiar power which was not present 
in the other manures ; and this constituent was supposed 
to be more conducive than other nitrogenous compounds 
to the growth of plants. 

The discovery of this constituent presented no difficulty. 
Chemical analysis showed that Peruvian guano was very 
rich in salts of ammonia, and that one-half of its nitro- 
gen existed in the form of ammonia. But ammonia was 
already well known as an element of nutrition for plants, 
and this afforded an easy solution of the rapidity which 
marked the operation of guano. Peruvian guano accord- 
ingly contained in a concentrated state in the ammonia 
one of the most important nutritive substances for plants, 
and this nutriment when dispersed in the soil could be 
directly assimilated by their roots. 

From this time forward a distinction was drawn be- 
tween the various kinds of nitrogenous manures, and 
' assimilable ' nitrogen was discriminated from that which 
was termed ' sparingly assimilable.' Assimilable nitrogen 
was understood to mean ammonia and nitric acid ; but 
the term ' hard of assimilation ' Avas applied to other 



296 AMMONIA AND NITEIC ACID. 

nitrogenous substances, which could not be made effective 
until their nitrogen had been converted into ammonia. 

The effect of guano in raising large crops of corn was 
undeniable ; hence it was according to theory assumed as 
incontestable, that its operation depended upon the 
amount of nitrogen contained in it ; it was further 
considered as certain, that ammonia was the most effective 
portion of the nitrogen in guano. It followed, therefore, 
as a matter of course, that the operation of guano could 
be produced by substituting a corresponding quantity of 
salts of ammonia ; and the partisans of this theory 
believed that to increase corn crops at pleasure, nothing 
further was necessary than to procure the requisite quan- 
tity of salts of ammonia at a reasonable price. Humus is 
the only thing wanting ; such was the earher opinion. 
ISTow, it is ammonia is the only thing wanting. 

This conclusion was an immense step in advance as 
regards the views of the importance of nitrogen for 
plants. Instead of attaching no determinate idea to the 
word ' nitrogen,' the term had now a fixed and definite 
meaning. That which formerly was called nitrogen was 
now termed ' ammonia,' an intelhgible, ponderable com- 
pound separable from all other substances which are 
likewise constituents of nitrogenous manures, and capa- 
ble of being used in experiments, in order to test the 
truth of the theory itself. 

If the operation of guano bore any proportion to its 
nitrogen, then a quantity of ammonia containing an equal 
amount of nitrogen must produce not only the same, but 
a much greater effect ; for one-half of the nitrogen in 
guano exists in the form which is difiicult of assimilation, 
whereas the ammonia could be entu-ely assimilated. 

If in any single experiment, the guano produced a 
powerful effect, and the corresponding quantity of am- 



EXPEEIMENTS WITH SALTS OF AMMONIA. 



297 



moiiia was inoperative or weaker, this experiment would 
be amply sufficient to confute the notion which had 
been attached to nitrogen. Eor if this notion was cor- 
rect, the ammonia ought to operate in all cases in which 
the guano operated, and exactly in the same manner. 
The oldest experiments in this direction were made by 
Schattenmann ('Compt. rend.' t. xvii.). 

He manured ten plots of a large wheat-field with sal 
ammoniac and sulphate of ammonia; an equally large 
plot remained unmanured. Of the manured plots, one 
received 162 kilogrammes (=356 lbs. Eng.) per acre ; the 
others received the double, treble, and quadruple quantity 
of each of these salts. 

The salts of ammonia (says Schattenmann, p. 1130) 
appear to exert a remarkable influence upon wheat ; for, 
only eight days after manuring, the plant assumed a deep 
dark-green colour, the sure sign of high vegetative power. 

The returns obtained by manuring with the salts of 
ammonia were the following : — 



Muriate of ammonia employed 



kilo. lbs. 

(1) 1 acre . none 

(2) 1 „ . 162= 356 

(3) 4 „ . 324= 712 



486 = 1069 
Average of the four 



kilo. lbs. 



324= 712^ 
486 = 1069 r 



Sulphate of ammonia employed 



kilo. 

(4) 1 acre . 162 

(5) 4 „ . 324 



486 
Average of the four 



kilo, 
324 
486 



Com 



kilo. owt. 
1182 = 23 
1138 = 22 



1174=23 
903=18 



Crop 



kilo. c\vt. 
2867 = 56 
3217 = 63 



3078 = 60 
3248 = 63 



Less 
Com 



kilo. owt. 
44=0-8 



8=0-15 
279=5-3 



More 
Straw 



kilo. cwt. 
348=6-8 



211=4-0 
381 = 7-5 



It is easy to see that the expectations which had been 
founded upon the deep dark-green colour were not 



298 AMMONIA AND NITRIC ACID. 

realised. The salts of ammonia were so far from exerting 
any influence in augmenting the corn-crop, that they 
diminished it in every experiment. In the crop of straw 
there was a small increase. 

In these cases the salts of ammonia had not enlarged 
the corn crop, but had produced the opposite effect from 
guano, by which corn crops are generally augmented. 

These experiments cannot, however, be regarded as 
decisive proofs against the view of the action of ammonia, 
because a comparative experiment with guano was not 
made at the same time and place. It is not impossible, 
that upon this particular field guano might have produced 
the same results. Some years later, Lawes and Gilbert 
published a series of investigations, which seemed to 
establish the operative power of ammonia, or rather of 
salts of ammonia. These investigations were intended to 
show, that the incombustible nutritive substances of wheat 
were not, of themselves, sufficient to enhance the fertility 
of a field, but that the crop of corn and straw stood 
rather in proportion to the supply of ammonia. In fact, 
that increased crops could be obtained by salts of am- 
monia alone, inasmuch as nitrogenous manures were pecu- 
liarly adapted for the cultivation of wheat. 

The experiments of Messrs. Lawes and Gilbert are very 
far, indeed, from proving the conclusions which they wish 
to draw ; they establish rather the fact that these gentle- 
men have not the slightest notion of what is meant by 
argument or proof. 

They did not attempt to discover whether salts of 
ammonia alone could produce from one portion of a field 
continuous larger crops than were yielded by an un- 
manured portion of the same field. 

Neither did they attempt to discover what crops would 
be yielded by an equal plot of ground by manuring with 



EXPERIMENTS OF LAWES AND GILBERT. 299 

superpliospliate and potash salts during a series of years. 
But in the first year they supphed a plot of ground 
for a whole series of years with the constituents of 
corn and straw, phosphoric acid and silicate of potash 
(560 lbs. of bone-earth rendered soluble by sulphuric 
acid, and 220 lbs. of silicate of potash), and manured 
it, in the following years, with salts of ammonia only, 
and they would have us to believe that the increased 
crops obtained under these circumstances were due to the 
operation of salts of ammonia alone ! 

The imperfect nature of the experiments made by 
Messrs. Lawes and Gilbert will appear, perhaps, more strik- 
ing, if the question which they pretend to solve is stated 
in another form. We will assume that the point to be 
proved was, that the high additional crops, yielded by a 
wheat field manured with guano, were due to the operation 
of the salts of ammonia in the guano, and that its other 
constituents had no share in the work. If the guano had 
been hxiviated with water, and two portions of a field 
had been manured, the one with guano, the other with 
the soluble constituents of an equal quantity of guano, 
only two cases could occur ; the crop of both plots would 
be either equal or unequal. . If the crops were equal, it 
would be manifest that the insoluble constituents of the 
guano had no effect : if the crop upon the plot manured 
with guano was greater, it would be certain that the 
insoluble constituents (mineral constituents, as Messrs. 
Lawes and Gilbert would term them) had some share in 
producing the additional crop. The extent of this share 
could perhaps be determined, if a third plot were 
manured with the insoluble constituents, i. e. witli the 
lixiviated residue of an equal quantity of guano. 

If an experimentalist, in carrying out his proof, in- 
stead of following this method, had, on the contrary, 



300 AMMONIA AND NITKIC ACID. 

lixiviated the guano, and manured a plot of ground in the 
Jirst year with the insoluble constituents of the guano, and 
in the subsequent years, with the soluble constituents — and 
if he had maintained that these soluble constituents, in 
other words, the salts of ammonia in the guano, had alone 
produced the high additional crops, and that these bore a 
proportion rather to the salts of ammonia than to the 
incombustible constituents in the guano, we should have 
good grounds for concluding that he had simply deceived 
himself ; for, in point of fact, the field had been manured, 
not with salts of ammonia alone, but with all the consti- 
tuents of the guano. 

What has here been said in reference to guano, 
which, as before mentioned, has the same effect as a 
mixture of superphosphate, potash, and salts of ammonia, 
may be hterally applied to the experiments of Lawes and 
Gilbert. 

They manured their field, in the first year, with a quan- 
tity of soluble phosphoric acid, lime, and potash, which 
very nearly corresponds with the amount of these sub- 
stances in 1750 lbs, of guano ; and in the subsequent 
years they applied salts of ammonia. The arable surface 
soil of the field had, by previous cultivation, been mani- 
festly exhausted of nitrogenous food ; and, under these 
circumstances, the only wonder would have been if the 
nutritive substances which operate in guano had been 
able, without ammonia, to yield as large a crop as 
with ammonia. 

These experiments are worth notice in the history of 
agriculture, because they show what statements could be 
laid before farmers, at a time when ignorance of first 
principles did not yet permit scientific criticism. 

With regard to the influence of ammonia and salts of 
ammonia, there was instituted in the years 1857 and 



EXPEEIMEXTS WITH SALTS OP AMMOKLY. 301 

1858, on the part of the General Committee of the Agri- 
cultural Society of Bavaria, a series of comparative expe- 
riments in the district of Bogenhausen, as to the opera- 
tion of guano, and various salts of ammonia containing 
an equal amount of nitrogen, the results of v^hich are 
decisive. 

The experiments were conducted upOn a field (a loam) 
which had gone through the usual rotation, and which, 
with ordinary farm-yard manure, had borne rye and then 
oats twice successively. Of eighteen plots in this field, 
each 1914 square feet in area, four were manured with 
salts of ammonia, and one with guano, one plot remained 
unmanured. 

As a starting point for estimating the quantity of 
maniu"e to be employed, it was assumed that 400 lbs. 
of guano per acre English (=493 lbs. avoir.) correspond 
to the full measure of farm-yard manure usually 
applied. According to this proportion, 20 lbs. ( = 
24f lbs. avoir.) of guano were reckoned for the area in 
question. 

The samples of good Peruvian guano selected were 
previously analysed, and in 100 parts a quantity of 
nitrogen was foimd corresponding to 15 •39 of ammonia. 
As a general rule, only one-half of the nitrogen in guano 
is present as ammonia ; the other half appears as uric 
acid, guanine, &c., of the operation of which upon the 
growth of plants little or nothing, as we have before 
observed, is known. But it was assumed that the nitrogen 
in these other substances was just as operative as that m 
the ammonia, and the quantum of the various salts of 
ammonia (which were hkewise analysed previously to 
ascertain exactly their amount of ammonia) was reckoned 
in accordance with this assumption. Accordingly, for the 
above 20 lbs. of guano, 1719 grammes (=3*75 lbs.) of 



302 AMMONIA AND NITEIC ACID. 

ammonia were computed as the equivalent ; and each 
of the other four plots received exactly the same quantity 
of ammonia, in the salt of ammonia employed for manure. 
It is clear that if an increased crop was obtained by 
means of the guano, and if this was due to the amount of 
its nitrogen, then each of the other four plots, having 
received the same quantity of nitrogen^ must necessarily 
be affected in exactly the same manner as if they, also, 
had been manured with 20 lbs. of the same guano. The 
results were as follow : — 

Comparative expeinments at Bogenhausen ivith guano and salts of 
ammonia containing equal quantities of nitrogen. 





Harvest, 1857.- 


— Baeley. 


Grain 


Straw 


grammes lbs. 
Manured with 5880 = 13 carbonate of 


ammonia 


grammes 
. 6335 


grammes 
16205 


„ 


4200= 9 nitrate 


,, 


8470 


16730 


Unmanured 


6720 = 14f phosphate 
6720 = 14| sulphate 
20 lbs. = 24f ay. guano 


)i 


. 7280 
. 6912 
. 17200 
. 6825 


17920 
18287 
33320 
18375 



Although each of the four plots had received the same 
quantity of nitrogen, still their respective crops did not 
correspond ; on the whole, the crop from the plots 
manured with salts of ammonia, corn and straw together, 
was in each case very little higher than that of the un- 
manured plot ; while the plot manured with guano 
yielded, for the same quantity of nitrogen, 2\ times more 
corn, and 80 per cent, more straw, than the average crop 
of the plots manured with salts of ammonia. 

In the subsequent year, this experiment was repeated 
in a similar manner in the same district with winter wheat. 
The field chosen, and to which six years previously farm- 
yard manure had been apphed, had borne winter rye, 
then clover, and then oats, for three years. The oat 
stubble was broken up and then twice ploughed : on the 



BOGENHAUSEN EXPEEIMENTS. 303 

12tli September, 1857, the seed was sown and harrowed 
in, on one day : immediately after the sowing there was a 
moderate thunder shower. 

Tlie field was divided into seventeen lots, each of 1900 
square feet, which were separated from each other by 
furrows ; each was separately sown and harrowed. The 
quantity of guano used was 18'8 lbs. (==23'3 lbs. avoir.), 
and the weight of the salts of ammonia employed was 
calculated from the amount of nitrogen in the guano, so 
that, as in the previous experiment, each plot received an 
exactly equal amount of nitrogen. The results were the 
following : — 

Experiment in JBogenhausen. 
Eesult of Harvest, 1858. — WrNTER-WHEAT. 

Corn Straw 

grammes grammes 

Manured with guano, yielded 32986 79160 

„ sulphate of ammonia (11-8 lbs. Eav.) . 19600 41440 

„ phosphate „ (11'9 „ „ ) . 21520 38940 

„ carbonate „ (10-6 „ ,, ) . 25040 57860 

nitrate „ ( 7-1 „ „ ) • 27090 65100 

Unmanured - . . 18100 32986 

These experiments show in the clearest manner that it 
is an error to refer the effect of a powerful nitrogenous 
manure chiefly to the nitrogen which it contains. 'No 
doubt it has a share in the operation of these manures, 
but their energy is not in proportion to the amount of 
nitrogen in them. 

If ammonia or salts of ammonia increase the produce 
of a field, their effect depends upon the nature of the soil. 
What we mean here by the nature of the soil is under- 
stood by every one ; the ammonia can engender in the 
soil no potash, no phosphoric acid, no silicic acid, no lime ; 
and if these substances, which are indispensable for the 
developement of the wheat plant, are not found in the 
soil, the ammonia cannot produce any effect whatever. 



S04 AMMONIA AND NITRIC ACID. 

If, then, in Schattenmann's experiments, and tliose at 
Bogenliausen, there were no resuhs from the sahs of am- 
monia, this did not arise from the fact of these salts being 
in themselves ineffective ; but they were inactive, because 
the conditions of their activity were wanting. Lawes 
and Gilbert supplied these conditions to their field, and 
hence ensured activity to the ammoniacal salts they used. 
The results obtained by Kuhlmann respecting the effect 
of salts of ammonia upon meadows are precisely similar. 
He manured a piece of meadow land with sulphate of 
ammonia, and obtained a crop of hay larger than the 
yield of the unmanured plot, because a certain quantity 
of phosphoric acid, potash, &c. was rendered active, 
which without the cooperation of salts of ammonia would 
not have been the case. On adding phosphate of lime to 
the salts of ammonia, the activity of the latter was 
enhanced in an extraordinary degree ; he obtained, — 

Return of hay, per hectare, 1844. 









Excess above the 








umnanui-ed plot 




kilo. 


kilo. 


kilo. 


(1) 


By manuring with 250 sulphate of ammonia 


6564 


1744 


(2) 


jj „ 333 sal ammoniac, with phosphate 








of lime 


9906 


6086 


(3) 


Unmanm-ed plot 


3820 


— 



Thus, by sulphate of ammonia alone, Kuhlmann ob- 
tained rather more than half as much hay again as the 
yield of the unmanured plot ; and by adding phosphate 
of lime he gained almost three times as much. 

Those who maintained the theory of the special im- 
portance to agriculture of nitrogen in manure, formed a 
similar notion about the cause of fertility in land. 

If, in fact, the efficacy of any manure depended on the 
enrichment of the soil with nitrogen, exhaustion could be 
explained only by the diminution of the store of nitrogen ; 
and the manure would restore fertihty when the nitrogen 



FERTILITY OF LAND NOT DUE TO ITS NITROGEN. 305 

which had been removed in the harvest was aeain 
supphed by it to the field. Accordingly, the unequal 
fertihty of land must be due to the unequal amounts of 
nitrogen contained in it ; and it would follow that the soil 
richer in nitrogen must be more fruitful than one which 
contained less of this element. 

This theory, too, came to a pitiful end; since that 
which was not true for manures could not possibly hold 
good for land. 

Every one who is acquainted with chemical analysis 
knows that among the constituents of the soil none can 
be approximately determined with greater accuracy than 
nitrogen. In an exhausted soil at Weihenstephan and 
Bogenhausen, nitrogen was determined by the usual 
method, and calculated to a depth of 10 inches. 

The field contained, per hectare, 



)genliausen 


Weihenstephan 


kilogr. 


kilogr. 


5145 


5801 



Nitrogen 

On both fields summer barley was cultivated in 1857, 
and the following returns were obtained, per hectare : — 





Bogenhausen 


Wcihenstepliau 




kilogr. 


kilogr. 


Corn 


413 


1604 


Straw 


1115 


2580 



1528 4184 



Thus, the field at Weihenstephan, containing about the 
same amount of nitrogen, yielded almost four times as 
much corn, and more than twice as much straw, as the 
field at Bogenhausen. 

In 1858, these experiments were repeated at Weihen- 
stephan with winter wheat, and at Schleissheim with 
winter rye ; the result was : — 

X 



306 AMMONIA AND NITRIC ACID. 

Nitrogen contained to the dejjth of 10 inches, per hectare, 

Schleissheim Weiliensteplian 

kilogr. kilogr. 

2787 5801 

Crop. 
Com . . 115 1699 

Straw . 282-6 3030 

397-6 4729 

The amount of nitrogen in tlie field at Sclileisslieim, as 
compared with that at Weilienstephan, bears tlie propor- 
tion of 1 : 2 ; whereas tlie crops are in the proportion of 
1 : 14. These facts are fatal to the opinion that there 
exists any connection between the amount of nitrogen in 
a soil, and its powers of production ; and in truth no one 
now entertains this belief. For since Kroker in 1846 de- 
termined the nitrogen in 22 kinds of soil from various 
districts, and discovered that even an unfruitful sand 
contained more than a hundred times, while in arable soils 
to a depth of 10 inches there were present from 500 to 
1000 times, more nitrogen than is necessary for a good 
crop, similar investigations have been made in all coun- 
tries, and Kroker's results have been confirmed. 

Since that period the fact has been generally admitted, 
that the great majority of cultivated soils are far richer in 
nitrogen than in phosphoric acid ; and that the relative 
proportion of nitrogen present, which had been adopted 
as the standard for calculating the value of manure, was 
quite inapplicable for estimating the productive power of 
land. 

Hence, between the chemical analysis of manm^eff, and 
that of the soil, there arose an irreconcilable contradic- 
tion. In the chemical laboratory the effective value of a 
manure could be accurately determined according to 
the per centage of its nitrogen ; but when the farmer 
liad incorporated his manure with the soil, the determina- 



DIFFERENT FORMS OF NITROGEN" IN THE SOIL. 307 

tion of tlie per centage of nitrogen in the ground was no 
longer of any use in estimating its productive power. 

This strange circumstance might well have excited 
suspicion against the theory of the preponderating influ- 
ence of nitrogen, for which, as already observed, there is 
not the slightest evidence in poiat of fact. But instead 
of this, the advocates of the theory maintained it stead- 
fastly, and endeavoured to explain the behaviour of the 
soil upon new and still more extraordinary grounds. It 
had been observed that a very small fraction of the quan- 
tity of nitrogen present in the soil, in the form of guano, 
farm-yard manm^e, or nitrate of soda, materially increased 
the crops ; whereas, the effect of other manures, which 
contained nitrogen not in the form of ammonia or nitric 
acid, was very unequal in respect of time, and, in the case 
of horn shavings or woollen rags, was extremely slow. 
This led to the assumption that the nature of nitrogen 
was as variable in the arable soil as in manures ; one 
portion was supposed to be in the form of ammonia or 
nitric acid, and this was, properly speaking, the effective 
part ; another portion, on the contrary, existed in some 
peculiar form which could not exactly be defined, and was 
quite ineffective. 

Hence the productive power of a soil was, according to 
this view, not in proportion to the entire quantity of 
nitrogen in it, but could only be measured by the nitric 
acid and ammonia which it contained. As the advocates 
of the theory about the effective operation of nitrogen had 
been accustomed to shirk proving the truth of their 
doctrine, as a matter of course they did not trouble 
themselves about adducing any positive facts in support 
of this extension of it. They behoved that they could 
estabhsh their point in the following way. 

When a crop contained in corn and straw as much 

X 2 



308 AMMONIA AND NITEIC ACID. 

nitrogen as was equivalent to six, four, three, or two per 
cent, of tlie whole quantity of nitrogen in the soil, the 
reason was that there were present in the field six, four, 
three, or two per cent, of active nitrogen, while the 
remaining 94, 96, 97, or 98 per cent, were inoperative 
nitrogen. 

■ The cause of the effect (the amount of active nitrogen 
in the soil) was consequently inferred from the effect (the 
amount of nitrogen in the crops). If more of the whole 
quantity of nitrogen was in an active form, then higher 
crops would foUow ; if the crops were lower, the reason 
was that there was a deficiency of active nitrogen. If in 
guano or farm-yard mamue additional active nitrogen was 
supphed, the crops would be increased. 

By taking a new standard for estimating the productive 
power of the soil, the former one for the valuation of 
manure was virtually abandoned. For when efficiency 
was allowed only to nitric acid and ammonia in the soil, 
and denied to all other nitrogenous combinations, it was 
evidently unwarrantable to place those nitrogenous com- 
pounds in manures, which were neither ammonia nor 
nitric acid, in the same class with these two elements of 
food. 

But in the classified estimate of manures, a high place 
was given to dried blood, horn shavings, gelatine, and the 
nitrogenous constituents of rape-cake, all substances 
which contain neither nitric acid nor ammonia. The 
favourable effect of these manures was, in the majority of 
cases, undoubted, but still not determinable by analysis. 
Of two fields, the one manured with rape-cake, the other 
not, the former yields a larger corn or turnip crop than 
the latter, but it is not possible to show that there was 
more ammonia in the one case than in the other. True, 
it was assumed that the nitrogenous compounds of these 



NITROGEN IS NOT UNDER TWO FORMS IN SOILS. 309 

manures, the albumen of the blood, the rape-cake, or the 
gelatine, was gradually converted into ammonia, and so 
became operative ; but it was taken for granted as a 
matter of course, that the so-called inoperative nitro- 
genous compounds present in the soil do not possess the 
power of yielding ammonia, or of being oxydised into 
nitric acid. 

It was well known, indeed, that if one of two fields 
contained more lime than the other, the one richer in lime 
often did not on that account produce more clover. Yet 
no one thought of assuming that the lime in the richer 
field existed in a two-fold condition, operative and in- 
operative, or that the active portion of the hme had 
caused the difference in the clover crops. 

It was also weU known that if two fields be manured 
with the same bone-earth, the one often gave a higher 
crop than the other, and yet no one thought of assuming 
that in the second field the inefficiency of the bone-earth 
was due to the fact that it had passed into a state of 
inactivity. 

It was further known, that the excess of no individual 
nutritive substance exercised any influence upon the pro- 
duce of a field ; but it was assumed that the case must be 
different with nitrogen. A surplus of that element, it 
was surmised, must act, and if it did not, the cause was 
not ascribed to the field, but to the nature and condi- 
tion of the nitrogenous compounds. 

From this we see that the notion of nitrogen exerting 
the principal influence in agriculture led to unexampled 
confusion of thought and to the most baseless and absurd 
suppositions. None of the advocates of tliis theory gave 
themselves the slightest trouble to extract from the ground 
one of the nitrogenous compounds, which were deemed 
inoperative, so as to study its nature ; but properties were 



310 AMMONIA AND NITRIC ACID. 

ascribed to them, of wliicli nothing could be known, 
because the things themselves were not known. 

As the advocates of this theory can say nothing about 
the nature of the nitrogenous compounds present in the 
ground, they want to make us believe that nothing at all 
is known about them. But no one, who has an acquaint- 
ance with chemistry, has the smallest doubt or uncertainty 
respecting the origin of nitrogen in the arable soil. It is 
derived either from the air, whence it is conveyed to the 
earth in rain or dew ; or from organic substances accu- 
mulated from a series of generations of dead and decayed 
plants, or else from animal remains contained in the earth, 
or incorporated with it by man in the form of excrements. 
Animal and human excrements, bodies of animals in the 
earth, corpses in their coffins, all vanish, with the ex- 
ception of their incombustible matters, after a series of 
years ; the nitrogen of their constituents is converted 
into gaseous ammonia, and is distributed in the surround- 
ing soil. The remains of extinct animal hfe which are 
embedded, to an enormous extent, in sedimentary strata, 
or which of themselves constitute whole masses of rock, 
attest the extraordinary distribution of organic life in the 
former ages of the earth ; and it is the nitrogenous con- 
stituents of these animal boches, passing over into am- 
monia and nitric acid, which still play an important part 
in the economy of the vegetable and animal world. 

K the smallest doubt could exist on this question, it is 
completely removed by the investigations of Schmid and 
Pierre (' Compt. rend.' t. xlix. pp. 711-715). 

Schmid examined (see Peters. 'Acad. Bull,' viii. 161) 
several specimens of Eussian black-earth (tscherno-sem) 
from the Government of Orel, and among them three 
from the same field, marked by him as 'virgin soil,' 
of which we may assume that it had never been subject 



NITEOGEN m THE DIPFEEENT LAYEES OP SOILS. 311 

to agriciiitural operations ; the amount of nitroo-en in this 
soil amounted to — 

Amount of nitrogen in the tsclierno-sem. 

Under the turf 0-99 per cent, nitrogen 

4 wersehoks ( = 7 inelies) deeper , . 0-45 „ „ 

Above the subsoil 0'33 „ „ 

If we assume a cubic decimetre (=61 cubic in.) of this 
earth to weigh 1100 grammes (=2-4 lbs.), then, calculating 
for the area of a hectare (=2^ acres), the ground would 
contain — 

Mlo. cwt. 
1 decimetre ( = 4 iucKes) deep . . . 10890 = 213 nitrogen 
1 „ „ deeper . . 4950= 97 „ 

1 „ „ „ . . . 3630= 71 



30 centimetres ( = 11-7 inches) deep . . 19470 = 381 „ 

In examining a soil in the neighbourhood of Caen, 
Pierre found in it 19620 kilogrammes ( = 385 cwt.) of 
nitrogen distributed, in the following manner, through 
a hectare to the depth of one metre (=3*3 feet). 

centimetres inch.es kilogr. cwt. 

In the first layer of 25=10 deep, the soil contained 8360 = 164 

„ second „ 25 — 50 = 10—20 „ „ 4959= 97 

third „ 50 — 75 = 20—30 „ „ 3479= 68 

„ fourth „ 75—100 = 30—40 „ „ 2816= 55 



19614 = 384 

Thus, according to both investigations, the uppermost 
layers, or the proper arable soil (about 10 inches deep), 
were the richest in nitrogen, while in the lower layers the 
amount decreased. 

Such a condition undeniably proves the origin of 
nitrogen in the arable soil. 

If the upper layers, which are constantly deprived of 
nitrogen by cultivation, contain more of this element than 
the lower, it necessarily follows that the nitrogen must 
have come from without. The analysis of the most 



312 AMMONIA AND NITRIC ACID. 

various kinds of soil in many different lands and districts 
shows that there is scarcely a single fruitful wheat soil 
which does not contain at least 5000 to 6000 kilogrammes 
( = 98 to 118 cwt.) of nitrogen per hectare ( = 2^ acres) to 
the depth of 25 centimetres ( = 10 niches) ; and the simplest 
comparison of the quantity of nitrogen in the soil, with 
that which is removed in the crops, proves that the 
latter amounts to a very small fraction, and that the land 
is exhausted of all other nutritive substances sooner than 
of nitrogen. 

The experiments of Mayer ('Ergeb. landw. u. agric. 
Versuche.' Mlinchen. Iter Heft, s. 129) show that the 
behaviour of arable soil with respect to alkahes in watery 
solution affords no conclusion as to the nature of the 
nitrogenous compounds therein contained. It had been 
assumed, that all nitrogen in the earth in the form of 
ammonia could be separated by distillation with caustic 
alkahes, and that the portion that was not thus separated 
did not exist as such. Mayer proved the incorrectness of 
this assumption ; he first discovered, that many earths 
rich in humous constituents when boiled for four hoiu-s 
(which may be considered equivalent to lixiviation for 
four hours wdth boihng water) still retained a very con- 
siderable quantity of ammonia. The earths employed in 
these experiments were (1) earth from the hollow trunk 
of a tree, (2) garden soil rich in organic matters, from 
the Botanic Garden, (3) strong clay soil from Bogen- 
hausen. 

Ammonia. 

One million miUigrammes ( = 2-2 lbs.) retained at the temperature of boiling water: 

milligi'. grs. milligr. grs. milligr. grs. 

(1) Tree soil, 7308 = 112 (2) Garden soil, 4538 = 70 (3) Clay, 1576 = 24 

K an arable soil after saturation mth ammonia, by 
being placed either in a weak solution of pm-e am- 



AJIMONIA EETAINED FIEMLY BY SOILS. 313 

monia, or in a confined space with ammoniacal gas, or 
over carbonate of ammonia, is then dried and exposed in 
thin layers in this dry state to the air for fourteen days, 
all the ammonia not intimately combined in the soil is 
evolved, and the same result may be produced by con- 
stant washing with cold water. Now if soils thus satu- 
rated, the ammonia of which has been accurately ascer- 
tained, are exposed to distillation with soda lye, it is found 
that a considerable portion of the absorbed ammonia is 
not separable in this way. In the following table, A ex- 
presses the quantity of ammonia respectively absorbed 
by various soils at the ordinary temperature of the air ; B, 
the quantity of ammonia retained by the same soils after 
twelve to fifteen hours' action of soda lye in a water bath. 

One million milligrammes (=2'2 lbs.) of soil from 

Havannah Schleisslieim Eogenhaiisen Clay soil 

milligr. grs. milligr. grs. milligr. grs. milligr. grs. 

A Ammonia . 5520 = 85 3900 = 60 3240 = 50 2600 = 40 

B „ . 920 = 14 970 = 15 990 = 15 470= 7 

Under these circumstances, it appears that the power 
of retaining a certain portion of the absorbed ammonia 
is very unequal ; the Havanna earth (a poor lime soil) 
retains a sixth of the absorbed ammonia, the" soil at 
Schleisslieim the fourth, that at Bogenhausen almost a 
third.* 

* We need not be surprised at this peculiar comportment, for it merely 
proves tliat part of tlie ammonia in the earth is contained in an entirely 
different form from that of a salt. The salts of ammonia are com- 
binations of ammonium, which can be easily decomposed by alkalies, 
aUvaline earths, and metallic oxides, the alkali taking the place of oxide 
of ammonium, or the ammonium being displaced by some other metal. 
But we have no reason to beheve, that the ammonia, which by physical 
attraction is fixed in the porous arable soil, yields its place to another 
body, and is separable by it, if the latter has not a stronger attraction 
for the soil. 

Carbonate of lime, in the cold, produces scarcely any effect upon 



314 AMMONIA AND NITRIC ACID. 

This explains the reason why an arable soil saturated 
with ammonia gives back only a portion after being 
heated with soda lye for several hours ; and it is rather, 
perhaps, the lengthened operation of water at a high 
temperature, than the chemical attraction of the soda, 
that gradually separates, in the form of gas, the ammonia 
fixed by the soil. In this operation there is no percep- 
tible hmit, where the evolution of ammonia ceases ; for 
even after twenty-five hours of continuous heating in a 
water-bath, the fluid which passes off has still an alkahne 
reaction. 

The above arable soils in their natural condition com- 
port themselves with a boihng solution of soda precisely 
as if they were partially saturated with ammonia. In the 
following table, A expresses the total quantity of nitrogen 
in the form of ammonia, which is obtained from various 
soils at a red heat with soda hme ; B, the quantity of 
ammonia which is separable from them after twelve to 
twenty-five hours' heating with a solution of soda. 

One million miUigrammes of eartli ( = 1 kilo. = 2-2 lbs.) from 

Havannah Schleissheim Bogenhansen Clay soil 

milligr. grs. milligr. grs. milligr. grs. milligr. grs. 

A . . . 2640=40-6 4880 = 75-0 4060 = 62-5 2850 = 44-0 . 

B . . . 510= 7-8 1270 = 19-5 850 = 12 830 = 12-7 

These numbers lead to some interesting considerations ; 
they show, among other things, that the third, fourth, or 
fifth part of all the nitrogen contained in the soil is sepa- 
rable in the form of ammonia ; and that after twenty-five 
hours' distiUation with a solution of soda, the fluid which 
passes off has still an alkahne reaction. 

As a soil saturated ivith a?7imonia retains, after five or 

snlpliate of ammonia ; but in an arable soO, -wliicli contains carbonate of 
lime, the salt of ammonia is completely decomposed : lime takes the 
place of the ammonia, the latter however does not become free, but 
enters into some other combination, upon which lime has no eifect. 



NITKOGEN IN SOILS AND FAKM-YARD MANURE. 315 

six hours' heating with a sohition of soda, a third, a 
fourth, or a sixth of the ammonia absorbed by it, and we 
cannot assert that the retained portion has changed its 
nature, and is no longer ammonia ; so from tlie comport- 
ment of the earth in its natural condition, and under the 
same circumstances, we cannot conclude that the nitrogen 
which by distillation cannot be obtained in the form of 
ammonia, does not, therefore, exist as such in the earth. 

Even if the experiments above described do not afford 
any proof that all the nitrogen in the ground is in the 
form of ammonia (a portion, besides, is in most cases pre- 
sent as nitric acid), there is, on the other hand, no proof 
furnished to the contrary. 

Strictly speaking, the discussion of the point in ques- 
tion does not depend on this proof ; for it is sufficient to 
show here, that the comportment of the soil with respect to 
the amount of nitrogen in it is exactly the same as that of 
farm-yard manure. Only a small portion of the nitrogen 
in farm-yard manure is separable by distillation with 
alkahes ; the much larger portion being obtained only by 
complete decomposition of the substances. 

According to Voelker's analysis, 800 cwt. of fresh farm- 
yard manure contained — ■ 







1854, November 


1855, AprU 






lbs. 


lbs. 


Nitrogen 


. 


514 


712 


Ammonia |.^^^^^g 


27-2 \ 
70-4 J" ' 


97-6 


74-4 



If we compare with this the amount of separable am- 
monia and the total nitrogen in the soil at Schleissheim 



and Bogenhausen, we have — 



800 cwt. of arable soil contain nitrogen 


ScMeissheim 

lbs. 

321-6 


Bogenhausen 
lbs. 
267-2 


Present as separable ammonia 


101-6 


68-0 



It is manifest, that when two soils, not particularly lich 
in nitrogen, contain just as much ammonia as an equal 



31G AMMONIA AND NITEIC ACID. 

weiglit of farm-yard manure, if we ascribe tlie effect of 
the latter merely to the amount of ammonia which it 
contains, then the unfruitfulness of the field at Schleissheim 
is entirely inexphcable. 

We assume that the entire quantity of nitrogen in 
farm-yard manure has a definite share in its operation ; 
and as the nitrogenous matters in the arable soil are ori- 
ginally identical with the substances which form the 
constituents of manures, it is impossible to ascribe to the 
one an effect which does not equally apply to the other. 

There can be no doubt that the nitrogenous compounds 
in the ground often exert no influence in increasing the 
crops, while those in the manures undoubtedly produce 
a favourable effect. Hence the operation of the nitro- 
genous compounds in the manure must have depended 
upon causes which the ground did not supply; and it is 
clear that the same efficacy can be given to the nitro- 
genous compounds in the soil, if the farmer will take 
care to bring into play the causes which produced the 
favourable operation in the manures. 

If we consider, for example, the crops yielded (see 
pp. 147 and 150) by the two fields at Schleissheim in an 
unmanured condition, and compare them with the quan- 
tity of nitrogen in the soil, the result is — 

Nitrogen, per hectare (= 2^ acres). 



To the depth of 10 inches. 


Produce. 




Corn Straw 


In Field 1 (p. 150), 1858 . 2787 kilo. 


115 kilo. 282 kilo. 


In Field 2 (p. 147), 1857 . 4752 „ 


644 „ 1656 „ 



Those who maintain that the crops depend upon the 
nitrogen in the soil, would judge the results of these two 
experiments somewhat in the following way : — 

The amount of nitrogen in both fields is as . , . 100:160 
The corn crops as ....... 100 : 560 



CEOPS NOT IN PROPOETION TO NITEOGEN IN SOIL. 317 

If the crops are in proportion to the quantity of 
effective nitrogen in the soil, it follows that the soil of 
Field 2 contained, not only altogether, but even propor- 
tionately, more than Field 1. If the corn crop in Field 
1 = 115 kilogrammes corresponded to the fraction of 
effective nitrogen in the whole amount of nitrogen ^= 
2787 Idlogrammes, then Field 2 ought to have yielded 
257 kilogrammes of corn, supposing that the relative 
proportion of active and inactive nitrogen were the same 
as in Field 1 (for 2787 kilogrammes, nitrogen : 115 kilo- 
grammes, corn =: 4752 kilogrammes, nitrogen : 257 kilo- 
grammes, corn). But, in fact. Field 2 yielded two and 
a half times as much corn ; and therefore the amount of 
active nitrogen in Field 2 was just in the same proportion 
greater. 

, This explanation, very simple in itself, is, however, 
opposed by the fact that both these fields manured in the 
same year with superphosphate of lime (prepared from 
phosphorite) (see pp. 147 and 150), gave the followmg 
returns : — 

Crop, per hectare. 

Corn Straw 

kilo. cwt. Mlo. cwt. 

1858. Field 1 mamixed with superphosphate of lime 654 = 12-8 1341 = 26-5 

1857. „ 2 „ „ 1301 = 25-5 3813 = 75-0 

Hence, by the application of three nutritive sub- 
stances, sulphuric acid, phosphoric acid, and lime, without 
any increase of the quantity of nitrogen in the soil, 
as much corn was obtained from Field 1, containing 
2787 kilogrammes, nitrogen, as from Field 2, con- 
taining 4752 kilogrammes. There was then in the 
former as much effective nitrogen as in the latter, but it 
was deficient in certain other substances indispensably 
necessary to produce an action. Its power to become 
active was first exhibited when these substances were 
added to the field. In like manner, the favourable 



318 AMMONIA AND NITRIC ACID. 

influence of superphosphate upon Field 2 was exhibited ; 
for the crop of this plot, when unmanured, did not 
correspond to the amount of active nitrogen which it 
contained ; but by the addition of superphosphate the 
crop rose to more than double. And when to the super- 
phosphate upon Field 1, 137 kilogrammes of common 
salt, and 755 kilogrammes sulphate of soda were added, 
there was a still greater increase, i. e. there were now 700 
kilogrammes of corn, and 1550 kilogrammes of straw, 
a still greater quantity of apparently inactive nitrogen 
having been rendered effective. 

The intelhgent farmer who reflects upon questions of 
this kind, will be led to the conclusion, that an essential 
difference may exist between his own practical experience 
and the theories of the school which seeks to explain 
them. When practice tells us that farm-yard manure, 
guano, and bone earth have restored or increased the 
crops in certain cases, no one can maintain that 
these are not real facts, or are not trustworthy. 
But the observations of the practical man extend no 
further than these facts ; he has not actually remarked 
that the increased crops were produced by the ammonia 
in the farm-yard manure, or by that in the guano, or by 
the nitrogen in the nitrate of soda ; all this he is led to 
believe by persons who themselves know nothing about 
the matter. 

It is certainly a most remarkable circumstance, occur- 
ring in no other trade or industry, that in most cases the 
farmer cherishes representations or theories, for the truth 
of which he lias no evidence ; nay, he seems even to give 
up completely the very idea of inquiring into their 
correctness. It is quite incomprehensible that he should 
allow himself to be guided and convinced by facts which 
have not been remarked by himself upon his own ground. 



CAUSE OF INACTIVITY OF NITEOGEN IN SOILS. 319 

but have been observed in altogether different districts, 
and which must at least remain doubtful as far as their 
application to his own land is concerned. 

If, during the last ten years, only one farmer in a 
thousand had resolved to institute experiments upon his 
own land with ammonia or salts of ammonia to test the 
theory, whether in fact this manure is useful beyond all 
others in increasing the corn crops, how soon and how 
easily would an accurate estimate have been formed of its 
true value by other farmers ! 

The simple reflection that not one of the substances 
nutritive to plants does of itself exert any influence upon 
their growth, and that several other substances must be 
present, if the first is to prove useful, should have brought 
him to the conclusion that the case cannot be otherwise 
with nitrogen ; and that the value of a manure cannot be 
measured by the amount of nitrogen which it contains ; 
for this presupposes that the nitrogen possesses an opera- 
tive power, which must manifest itself under all circum- 
stances, and that the money which the farmer lays out in 
its purchase will always ensure an adequate return. 

Now, when his common sense tells him that such a 
supposition is impossible, and that he has only to open his 
eyes to observe by innumerable facts that ammonia is no 
exception to other nutritive substances, he will of himself 
come to the conclusion that the inactivity of the great 
mass of nitrogen in his field is not due to any condition 
pecuhar to itself, which science can neither investigate nor 
explain, but that it is inactive, just as phosphoric acid, 
potash, lime, magnesia, silicic acid, and iron, are inactive, 
when there is wanting in the ground one of the conditions 
necessary to make them available. 

The theory that by far the greater portion of the nitro- 
gen in the ground is incapable of serving for the nutrition 



n-IO AMMONIA AND NITRIC ACID. 

of plants, cannot be proved by the fact that the crops do 
not bear any proportion to the amount of nitrogen in the 
soil ; for were this the case, then all soils must be equally 
abundant in all other conditions for the growth of plants, 
and everywhere possess the same geological and mechani- 
cal condition. But this assumption is impossible, for on 
the whole surface of the globe there are not two districts 
in which the soils are identical in these respects. 

This theory must be strenuously opposed, not only 
because it is false generally, and that it has never yet been 
proved to be true even in a single case, but still more on 
account of the pernicious influence which it exercises 
upon the practice of the farmer. For since it induces 
him to suppose that it is impossible to give the necessary 
efficacy to the store of nitrogen in his land, he will never 
think even of attempting to do so. Being convinced 
beforehand that he need not try to raise the treasure 
buried in his field, he never even makes the attempt. 

Since the exact observation made in the cultivation of 
entire countries and divisions of the globe for centuries 
past, and also well-established facts, make it probable 
that a source of nitrogenous food exists, which ensures 
annually to a cultivated field without the husbandman's 
aid the return of a portion of the nitrogen, and in a ro- 
tation the whole amou.nt of that substance which has been 
taken away in the crops ; and further, that the field may 
be exhausted of every other nutritive substance, however 
great its store in the ground may be, because they are 
never spontaneously restored to the soil by nature — 
whereas this can never happen to nitrogen ; then it is 
contrary to all the rules of logic in any given case, to 
ascribe without closer examination the exliaustion of 
a soil above all other things to a loss of nitrogen. 

We might suppose, that apart from the suggestions of 



SUPPLY OF AMMOMA FEOM THE AIK. 321 

common sense, that the palpable advantage wliich would 
accrue to the farmer imperatively demands that he should 
take all possible pains to verify the correctness of this 
fact, and to discover how much nitrogenous food is 
annually restored to him by the atmosphere. For when 
he knows how far upon the whole he may calculate upon 
this source, he can easily arrange his system of cultivation 
to make it most profitable to him. If the atmosphere 
supplies him with the whole amount of nitrogen which 
he removes from his field by a rotation, then he can 
direct his thoughts to the means of keeping his whole 
farming operations going in the most effectual manner 
with the store which he annually collects in his manure 
heap, without spending any money upon nitrogenous food 
for his plants. If he finds that the atmosphere restores 
only a portion of that which has been taken away, and he 
accurately knows what this portion amounts to, then as 
circumstances require, he can, with judicious economy, 
supply from other sources what is lacking ; or he may so 
arrange his system of cultivation as to make the supply 
of nitrogen from natural sources cover what is removed 
in the crops. 

Every advance in an industrial pursuit has a definite 
standard of value in the price of the products ; and no 
sensible man would call an alteration in the mode of con- 
ducting a business by the name of improvement, unless 
the price of the products covered the cost of production. 
When the price of guano exceeds a certain limit, so that 
the crop realised does not bear a proper proportion to 
the outlay of capital and labour, this very circumstance 
prevents its application. 

From this point of view farmers might long ago have 
perceived that the question about the necessity of supply- 
ing ammonia to increase the crops of corn, includes 

Y 



322 AMMONIA AND NITRIC ACID. 

another question, whether, on the whole, progress in this 
respect is, or is not, possible in agricultural practice. 

A few considerations only are necessary to bring the 
farmer to the conviction, which I myself entertain, that if 
increased production depends upon an augmentation of 
nitrogenous food in the soil, we must at once renounce 
all idea of improvement. For my own part, I am much 
more inchned to beheve, that progress is only possible 
and attainable if the farmer restricts himself to that 
store of nitrogen which he can collect upon his own 
ground, avoiding as much as possible all purchase of 
nitrogenous food from other quarters. 

On the average, all the experiments of Lawes in 
England have shown, that for one pound of salts of 
ammonia in manwes, two pounds of wheat may he 
reaped. 

These results, we must remember, were obtained from 
a field in which one acre without manure of any kind 
was able to yield, for seven years consecutively, 1125 lbs. 
of corn and 1756 lbs. of straw ; and that all the plots 
manured with salts of ammonia also received phosphate 
and sihcate of potash.* 

On an average, Lawes manured his fields with 3 cwt. 
of salts of ammonia, and thereby he obtained half as 
much corn again as the unmanured plot yielded. 

We will now assume that the extra crop obtained was 
exclusively due to the salts of ammonia ; we will further 
suppose that all soils are inexhaustible in phosphoric 

* On this point Lawes says ('Jotirnal of the Eoyal Agr. Soc. of Eng.,' 
V. xiv. p. 282), that for the production of one bnshel of wheat (=:64 to 
65 pounds, containing 1 pound of nitrogen) which the soil was made to 
yield above its natural power, 5 pounds of ammonia were requisite 
( = 16 pounds of sal ammoniac, or 20 pounds of sulphate of ammonia). 
He adds, however, that in no single experiment did the extra crop 
obtained correspond to this estimate. 



CALCULATION OF AMMONIA EEQUIKED FOE SAXONY. 323 

acid, potash, lime, &c. ; and consequently, that the con- 
tinuous apphcation of salts of ammonia would involve no 
exhaustion of the soil. If we now reckon how much 
salts of ammonia, by weight, would be necessary for the 
kingdom of Saxony, in order to obtain half as much 
corn again as the unmanured land produces, the result is 
the following : — The kingdom of Saxony comprised, in 
the year 1843, 1,344,474 acres (1 acre=l'368 Eng. 
acre) of arable land, exclusive of vineyards, gardens, 
and meadows. If we suppose that each acre yields one 
corn-crop in two years, and that 4 cwt. salts of ammonia 
had to be applied in the way of manure, the kingdom of 
Saxony would requk-e annually 2,688,958 cwt. =134,447 
tons of salts of ammonia. 

Those who possess even a slender acquaintance with 
chemical manufacture, and know from what raw mate- 
rials (animal refuse and gas water) salts of ammonia are 
procured, must easily see that all the manufactories in 
England, France, and Germany put together, could not 
produce so much as the fourth part of the salts of 
ammonia requked by comparatively a very small country, 
in order to increase its products in the manner proposed. 

With a similar distribution we can easily calculate how 
much salts of ammonia would be required for the 
German provinces of Austria with 11 milhon jochen 
(1 joch= 1*422 Eng. acre) of arable land ; for Prussia, 
with 33 milhon morgen (1 morgen=0-631 Eng. acre) ; 
for Bavaria, with 9 milhon tagwerk (1 tagwerk= 0-842 
Eng. acre) ; and even if it were possible to quadruple 
the manufacture of salts of ammonia, this would have 
no material influence upon the crops. 

The cheapest ammonia is conveyed to Europe in 
Peruvian guano, which, taking a high average, contains 
16 per cent. 



324 AMMONIA AND NITRIC ACID. 

Peruvian guano is principally used in tlie cultivated 
lands of Europe, as in England, France, the Scandinavian 
countries, Belgium, tlie Netherlands, Prussia, and the 
German States, comprising, exclusive of Austria, 120 mil- 
lions of inhabitants. Now if we suppose that upon these 
lands for centuries to come 6 million cwt. (=300,000 
tons) of Peruvian guano, containing 360,000 cwt. of 
ammonia, were annually applied, and that it was pos- 
sible, with the means at present at our disposal, by 5 lbs. 
of ammonia to raise 65 lbs. additional of wheat, or its 
equivalent value, then the increased crop of corn would 
just reach so far as to give each individual in the commu- 
nity 2 Ihs. of corn a day for two days in the year. 

If we assume 2 lbs. of corn or its equivalent to be the 
average amount of nutriment required by an individual, 
this makes 730 lbs. annually. According to the supposi- 
tion made above, 36 million pounds of ammonia would 
produce thirteen times as much =46 8 million pounds of 
corn or its equivalent, whereby 641,000 individuals 
could be nourished for a year. 

Supposing the population of England and Wales to 
increase only 1 per cent, annually, this makes 200,000 
individuals in one year, and 600,000 in three years. 
Now the cereals hypothetically raised by help of the 
ammonia in 6 million cwt. of guano imported from 
abroad, would suffice but very few years to support the 
increased population of England and Wales. 

And what would be the state of things six or nine 
years afterwards in England or Europe, if we were 
actually dependent upon a foreign importation of am- 
monia, for the support of the increasing population ? 
Could we import 12 million cwt. of guano in six years, 
or 1 8 million in nine years ? 

We know most positively, that in a few years the 



COST OF AMMONIA. 325 

source of ammonia in "guano will be exhausted ; that we 
have no prospect of discovering a new and richer source ; 
that the annual increase of population, not only in 
England but in all European countries, is more than 1 
per cent. ; and, finally, that in proportion to the mcrease 
in the population in the United States, Hungary, &c., a 
corresponding diminution must follow in the exportation 
of corn from those countries. From these considerations 
the hope of augmenting the crops of a country by the 
importation of ammonia must appear utterly vain. 

Li Germany, a pound of wheat costs at present 
4 kreutzers (l^d.) ; a pound of sulphate of ammonia, 
9 kreutzers (^hd.) ; and if it were possible with a pound 
of this salt, added to our ordinary manures, to produce 
2 pounds more of wheat, then for every outlay of one 
florin (2s.) in money, the German farmer would receive 
53 kreutzers (Is. 9d.) in corn. This relation of outlay 
to income is evidently well known in practice, for up to 
this moment salts of ammonia have nowhere come into 
general use ; and though many manufacturers of manure 
add a certain quantity of ammonia to their productions, 
this is chiefly to humour the fancy of farmers for this 
substance ; but none of them can tell what advantage 
results from this addition. This prejudice will soon dis- 
appear of itself, when farmers have learned to make a 
proper use of the nitrogenous food which nature supphes 
spontaneously to the land without any aid on their part. 

The abundant supply of nitrogenous food in the soil, 
the increase of the same in well-cultivated ground, the 
examination of rain-water and of the atmosphere, all 
facts observed in cultivation in general, prove that, even 
with the highest system of farming, the soil is not ex- 
hausted in its store of nitrogenous food, and that conse- 
quently there is a circulation of nitrogen, hke that of 



326 AMMONIA AND NITEIC ACID. 

carbon, which presents to the farmer the possibihty of in- 
creasing his store of active nitrogen in the soil. 

The extraordinary effect of superphosphate of hme in 
augmenting the crops of corn, turnips, and clover, almost 
without exception, upon all German lands to which these 
non-azotised manures have been applied ; the operation 
of the newly-introduced Baker and Jarvis guanos* (which 
contain no ammonia) ; the action of lime, salts of potash, 
gypsum, &c., all show without doubt that an accumula- 
tion of nitrogenous food has taken place in the soil, the 
source of which was, until lately, quite obscure. 

We had reason enough to beheve in a partial restora- 
tion to the soil of nitrogenous food by air and rain, but 
that it should be augmented was quite unexplained ; 
because this presupposed that ammonia and nitric acid 
were produced from the nitrogen of the atmosphere, in 
evidence of which we had no facts whatever. Very 
recently this source of the increase of the nitrogenous 
food of plants was discovered by Schonbein, and the 
problem was solved in the most unexpected manner. 

In his experiments upon oxygen, Schonbein found that 
the wliite fume emitted by a piece of moist phosphorus 
is not, as was previously believed, phosphorous acid, but 
nitrite of ammonia. I myself had an opportunity of 
seeing this proved at a lecture, illustrated by experi- 
ments, which Schonbein dehvered at Munich in the 
summer of 1860. It is probable, as he states, that in 

* From a communication in tlie ' Official Gazette,' No. 3, ^of 1st 
March 1862, for the Agric. Union in Saxony, the following crops per 
acre were obtained in 1861 : — 

Wheat 
Corn Straw 

3 cwt. Jarvis guano produced . 2244 lbs. 4273 lbs. 

3 „ Baker „ „ . 2929 „ 5022 „ 

6 „ steamed bones „ . 3015 „ 4755 „ 

Unmanured „ . 1955 „ 3702 „ 



FOEMATION OF NITEITE OF AMMONIA. 327 

this reaction the nitrogen of the atmosphere, by a kind 
of induction, combines with three equivalents of water, 
whereby on the one hand nitrous acid, and on the other 
ammonia, are formed ; just as is well known that under 
the influence of a higher temperature, nitrite of ammonia 
is decomposed into water and nitrogen gas. The most 
strikiug fact is, this salt is formed under circumstances 
which we should have been led to suppose were precisely 
those opposed to its formation ; but the production of 
the peroxide of hydrogen (so easily decomposed by 
heat), during the slow oxidation of gether, which is at- 
tended by a perceptible evolution of heat, is a fact not 
less certain, and hitherto equally unexplained. 

The formation of nitrite of ammonia during this slow 
process of oxidation made it probable that it takes place 
everywhere on the earth's surface where oxygen enters 
into combination ; and consequently that the same pro- 
cess, whereby carbon is converted into carbonic acid, 
forms also an ever-renewing source of nitrogenous food 
for plants. 

Soon afterwards, Kolbe showed (' Annal. d. Chem. u. 
Pharm.' bd. 119, s. 176) that if a flame of hydrogen gas 
is allowed to burn in the open neck of a flask containing 
oxygen, the interior is filled with the red fumes of nitrous 
acid.* 

Further, Boussingault observed that, in the consump- 
tion of common illuminating gas, the water in Lenoir's 
gas machine contained ammonia and nitric acid ; and 
shortly after, Bottger mentioned, in the ' Annual Eeport 
of the Physical Society of Frankfort' (meeting of Nov. 2, 
1861), that, according to his experiments, not only in the 
case of hydrogen, but generally when hydro-carbons 

* The formation of nitrons acid in eudiometrical experiments was 
already known. 



328 AMMONIA AND NITEIC ACID. 

were burned, a certain quantity of nitrite of ammonia 
was always formed, together with water and carbonic 
acid. Ahnost contemporaneously with this notice, I 
received from Schonbein a written communication an- 
nouncing the very same results which he had obtained in 
the same way, so that no doubt can remain as to the 
correctness of this fact. 

The practical farmer, who is really anxious to improve 
his method of cultivation, must be led by these un- 
doubted facts to determine upon ascertaining, with the 
greatest clearness, the effect of nitrogen in his manures. 
Before he has been convinced that the atmosphere and 
rain convey the necessary amount of nitrogenous food to 
his plants, no one could expect him to renounce the 
employment of ammonia as a manure. When it is as- 
serted that the farmer can give a maximum of fertility 
to his land without supplying to it any nitrogenous 
matter, it is not meant that he must renounce the use of 
farm-yard manure ; but the assertion implies the existence 
of the latter, and is, in fact, based upon it. 

For the restoration or augmentation of productive 
power in exhausted corn-fields, it is absolutely necessary 
that the arable soil should contain a surplus of all nutri- 
tive substances for cereal plants, nitrogenous among 
others, but no one in greater proportion than the rest. 
It is assumed that the farmer by a right succession of 
crops, that is, by a proper proportion between his corn 
and fodder fields, is always in a position, by carefully 
husbanding the ammonia in his farm-yard manure and 
avoiding all unnecessary waste, to provide the arable soil 
with such a surplus of nitrogenous food as Avill corres- 
pond to the proportion of the other nutritive substances 
therein stored ; and that the atmosphere annually makes 
up what he removes in his crops. 

The nitrogenous food conveyed by the atmosphere and 



AMMONIA COLLECTED BY FODDER PLANTS. 



329 



rain, is upon the whole sufficient for his cuUivated plants, 
but not enough for many of them in point of time. In 
order to give a maximum crop, many plants require, 
during the period of vegetation, much more than the air 
and rain afford in that time ; and therefore the farmer 
makes use of fodder plants in order to increase the crops 
of his corn-fields. The fodder plants, which thrive 
without rich nitrogenous manure, collect from the ground 
and condense from the atmosphere, in the form of blood 
and flesh constituents, the ammonia which is supplied 
from these sources ; and the farmer, in feeding his horses, 
sheep, and cattle with the turnips, clover, &c., receives, 
in their solid and fluid excrements, the nitrogen of the 
fodder in the form of ammonia and products rich in 
nitrogen ; and thus he obtains a supply of nitrogenous 
manures or nitrogen, which he gives to his corn-fields. 

The rule is, that for certain plants, weak in develope- 
ment of leaf and root, and which have but a short 
period of vegetation, the farmer must compensate by the 
quantity of manure for the time which is wanting for 
the absorption of the requisite amount of nitrogen from 
natural sources. 

It is easy to see that the accumulation of nitrogenous 
food by farm-yard manure in the uppermost layers of the 
ground, so very important for the perfect growth of 
cereal plants, must chiefly depend upon the successful 
growth of fodder plants. 

The unmanured fields in the Saxon experiments — 





Yielded 
altogether 


Lost by 


Eeceived 






sale of 
crop 


in farm-yard 
manure 


Clover 
crops 


1851— 1854 


Nitrogen 


Nitrogen 


Nitrogen 




lbs. 


lbs. 


lbs. 


lbs. 


Cunnersdorf . 


342-4 


78-4 


263-6 


9144 


Mausegast . 


279-5 


84-1 


175-0 


5538 


Kotitz .... 


160-9 


54-8 


106-1 


1095 


Oberbobritzsch 


127-7 


57-2 


70-5 


911 



330 AMMONIA AND NITEIC ACID. 

It is easily perceived from this table tliat the quanti- 
ties of nitrogen which could be obtained from the field 
and restored in the form of farm-yard manure, bear a 
proportion not exact but sufficiently well marked, to the 
crops of clover produced by the field ; and there can be 
no doubt that the farmer who takes the right way to 
make his fodder plants thrive, obtains at the same time 
the means of enriching his arable soil with a surplus of 
nitrogenous food for his corn-plants. 

We do not mean to imply that in every possible case 
the farmer must renounce the idea of supplying to his 
land ammonia from other quarters ; for soils vary so very 
much in their nature, that even though we can assert 
that by far the greater proportion of them may not 
require a restoration of nitrogenous food, yet this will 
not hold good for all without exception. In a soil rich 
in hme and humous materials, in consequence of the 
process of decay going on, a certain quantity of the 
ammonia fixed in the earth is converted into nitric acid, 
which is not retained by the soil, but is conveyed into 
the lower layers in the form of salts of lime or magnesia. 
Under certain circumstances, this loss may amount to 
much more than is compensated by the atmosphere, and 
for such fields a supply of ammonia Avill always be useful. 
The same holds good for certain soils which have not 
been tiUed for many years, and in which, by the opera- 
tion of the causes above-mentioned, the necessary sur- 
plus of nitrogenous food, formerly present, is gradually 
expended. On recommencing the cultivation of such 
soils, the employment of nitrogenous manures will at 
first produce a remarkably beneficial effect. Afterwards, 
these too requh-e no further supply. 

There is one reason which excites in the farmer's mind 
a prejudice in favour of nitrogenous manures, and that 



EFFECT OF NITROGENOUS FOOD. 331 

is the great inequality in the appearance of the young 
crops, when such manures are apphed in comparative 
experiments. The cereal plants upon fields manured 
with guano or nitrate of soda are distinguished before 
others by a deep green colour, and by broader and more 
numerous leaves ; but the harvest is generally far from 
corresponding to the expectations raised by this promis- 
ing appearance. Upon a field excessively rich in nitro- 
genous food, there is a kind of rankness in the early 
growth hke that produced by a hot-bed : the leaves and 
stalks are watery and weak, in consequence of the want 
of time in their over-hasty growth to absorb contempo- 
raneously from the soil the necessary quantity of sub- 
stances, such as silicic acid and Hme, capable of commu- 
nicating to their organs a certain solidity and power of 
resistance against those external causes which endanger 
their existence. The stalks fail to acquire the necessary 
stiffness and strength, and are always hable to be laid, 
especially upon lime soils. 

This injm^ious influence of excess of nitrogenous food 
is particularly remarkable in the case of the potato plant ; 
for if it grows upon a soil excessively rich in nitrogenous 
food, and the temperature should suddenly fall and wet 
weather supervene, the plant is often attacked by the so- 
called potato disease ; while a neighbouring potato field 
merely manured with ashes shows no trace of it. 

Among all the many experiments which have been 
hitherto made by farmers to improve their land, there is 
not one instituted for the purpose of ascertaining the 
actual condition of their soil, or of seeking proofs for the 
correctness of the notions which they had once adopted. 
The reason of theu indifference about obtaining proofs for 
their views chiefly consists m this, that the practical man, 
like the artisan, is guided in his business not by ideas. 



332 AMMONIA AND NITRIC ACID. 

but by facts. Hence it is quite indifferent to him, 
whether the theory, or what he dignifies by that name, is 
correct or not, as he does not regulate his proceedings in 
accordance with it. 

Many thousand farmers, who have not the remotest 
conception of the nutrition of plants or the composition 
of manures, apply guano, bone earth, and other manures, 
to their fields, with fully the same effect and with even the 
same skill as others who possess such information ; nor do 
the latter derive any manifest advantage from their know- 
ledge, because it is not of the right kind ; for example, 
the chemical analysis of manures is rather calculated for 
ascertaining their purity, and for determining theu^ price, 
than as a means for making us acquainted with their 
effect upon land. 

In England bone earth was used and valued as a 
manure half a century before any idea was formed as to 
what its operation was due ; and when afterwards the 
erroneous theory was adopted that its effect depended 
upon the nitrogenous gelatine which it contained, this 
view did not exert the slightest influence upon its 
employment. 

The farmer manured his field with bone earth, not on 
account of its nitrogen, but because he wished to have 
larger crops of corn and fodder, and because experience 
told him that he could not expect them without bone 
earth. 

An agricultural practice, founded upon a simple ac- 
quaintance with facts, without any idea of their nature, or 
one based on the exhaustion of the land, may be conducted 
by a person of very limited intelhgence, nay, the most 
ignorant man may be fitted for the purpose, by the mere 
statement of facts to him. But a rational pursuit of agri- 
culture, which, with the greatest economy of capital and 



A EATIOJSTAL AGRICULTURIST. 333 

labour, can obtain from a field continuously without ex- 
haustion the highest crops it is capable of yielding, 
requires a large compass of knowledge, observation, and 
experience, more perhaps than in any other business. 
For the rational agriculturist must not merely know all 
the facts with which the illiterate peasant is acquainted, 
but he must also be able to appreciate them at their 
proper value ; he must know the reason of all his proceed- 
ings, and what effect they may have upon his land. He 
must be able to interpret what his field tells him in the 
phenomena which he observes in practice ; in a word, he 
must be a thorough man, and not a half-and-half creature 
who knows no more about his actions than a tom-cat, 
with just skill enough to catch gold fish in a basin of 
water.* 

* If we compare tlie theoretical views expressed in tlie works of 
confessedly good practical farmers with the system of husbandry which 
they have found by their own experience to be the best, Ave observe 
the most irreconcilable contradictions between the two. 

Walz ('Communications from Hohenheim,' No. 3, 1857) disputes 
both these propositions, viz. : — 

' That the removal of the mineral constituents in the cro]DS, ivitliout 
compensation, produces sooner or later lasting unfruitfulness as a con- 
sequence.' 

' That if a soil is to maintain its fertility continuously, the removed 
mineral constituents must, sooner or later, be returned to it, i.e. the 
comjDosition of the soil must be restored.' 

And gives as his opinion that both these propositions are at present 
applicable only to soils of the worst kind, which needed a supply of 
mineral matters from the very beginning. 

Now, if we turn to the ' Application of his theory to practice ' (page 
117), we would naturally suppose that he would never trouble himself 
about any compensation ; but it soon appears that he is far fi-om believing 
in the truth of his oAvn doctrines. He lays the proper stress upon the 
restoration of potash, lime, magnesia, phosphoric acid, gypsum, guano, 
bone-earth, marl, and farm-yard manure; and lays down the following 
rule : — ' That the farmer, to keep his groimd in uniformly increasing 
fertility, must not remove more in liis crops than the products of the 



334 AMMONIA AND NITRIC ACID. 

atmosphere and the assimilable mineral substances added annually to 
the soil by the action of the weather.' He says further : — ' If the 
farmer were to confine his business entirely, e.g. to the manufacture of 
heer, spirit, sugar, starch-meal, dextrine, vinegar, &c., and the sale of 
animal products merely to butter, using up the skimmed milk ; if for his 
dairy he were to buy none but fiill-grown cows and not breed them 
himself, thus endeavoui'ing to keep the phosphates upon his farm, then 
he would not only preserve continually the mineral substances in his 
store of mantue, but he would also increase them by the yearly process 
of disintegration, unless he preferred to alienate the latter in his produce 
(s. 142). 

Hence the point of his practical teaching, in direct opposition to his 
theoretical, is that, in order to obtain uniform crops, great care must 
be taken to maintain and restore the composition of the soil. 

The practical man proves that the notions which he has conceived 
are entirely inapplicable in his practice ; and that the scientific 
principles which he disputes are precisely those by which he is un- 
consciously guided. Sound practice and true science are ever in 
unison ; and a contest on these matters is possible only between two 
persons, one of whom does not understand the other. The chief fault 
lies in want of precision in defining things, and in using indefinite or 
vague language to express our ideas. 

The opinion of Eosenberg-Lipinsky (see his ' Practical Agriculture,' 
b. ii. Breslau : E. Trewends, 1862), is ' that no kind of plant actu- 
ally exliausts the great storehouse of the soil ' (p. 738) ; and further, 
'■ that plants, directly and indirectly, return to the soil more strength 
than they take from it' (p. 740). This opinion is thus modified 
(p. 742) : — ' when therefore the farmer does not take sufficient care 
that the more important magazine of nutriment, the soil, receives 
at the right time, and in proper quantity, the necessary compensation 
for that which is inevitably consumed, the picture of exhaustion which 
the cultivated plants manifestly wear, cannot possibly be charged upon 
their consumers, but the blame is ivholhj and solely attributable to the 
farmer himself.' Further, at p. 740, he says, ' Only in those plains, 
where the injustice of the elements, or of man, has violently distiu-bed 
the natural laws of the nutrition of plants, does the scanty vegetation of 
the wild flora indicate the exhaustion of the soil.' 



335 



CHAPTER Xn. 

COMMON SALT, NITRATE OP SODA, SALTS OF AMMONIA, 
GYPSUM, LIME. 

Effect of these substances as elements of food ; their effect on the condition 
of the soil — Kuhlmann's experiments with common salt, nitrate of soda, 
and salts of ammonia; experiments with the same substances in Bavaria ; 
conclusions : these matters are elements of food ; they are chemical 
means for preparing the soil ; they cause the distribution of the food in 
the soil in the form proper for the growth of plants — Experiments by 
Pincus with gypsum and sulphate of mag-nesia on clover ; decrease of 
flowers and increase of stem and leaves of clover by sulphates ; the crop 
is not in proportion to the quantity of sulphates used — Effect of gypsum 
not yet explained ; indication in the comportment of clover soils with 
solution of gypsimi ; such solution disperses potash and magnesia in the 
soil — Manures, their effect not explained by the composition of plants 
produced by them— Composition of the ash of clover manured with dif- 
ferent substances — Effect of lime ; experiments of Kuhlmann and Trager ; 
comportment of lime-water with soils. 

THESE salts are employed in agriculture in many cases 
with marked success as manure ; and since nitric acid, 
soda, ammonia, sulphuric acid, and lime, are nutritive 
substances, the explanation of their efficacy presents no 
difficulty. But they also possess other peculiarities, by 
which they aid and promote the action of the plough and 
of mechanical tillage, as well as the influence of the 
atmosphere upon the condition of the field. This influ- 
ence is not always clear to our minds, but it is not less 
certain. 

We have every reason to believe that where the crops 
are increased by manuring with common salt alone, or 
when the favourable influence of salts of ammonia or nitrate 



336 COMMON SALT, NITRATE OF SODA, ETC. 

of soda is augmented by the addition of common salt, the 
operation of the three salts essentially depends upon their 
power of diffusing the nutritive substances present in the 
soil, or of preparing those substances for absorption. In 
what manner this takes place with all is not yet explained. 
The first trustworthy experiments in this direction were 
made by F. Kiihlmann (' Annal de Chim.' 3 ser. t. xx., 
p. 279). In the year 1845 he manured a natural meadow 
with sal ammoniac, sulphate of ammonia, and common 
salt ; and obtained the following quantities of hay : — 

Croj) of hay, per hectare, 1845 and 1846. 

Increased crop 



Unmanured 11263 kilos. 

Sal ammoniac, yearly 200 kilos. . 14964 „ 3700 kilos. 

200 „ ^ 
Common salt „ 200 „ J 



16950 „ 5687 



Another meadow jdelded : — 

Crop of hay, per hectare, 1846. 

Increased crop 
Unmanured . . . . . 3323 kilos. — 
Sulphate of ammonia 200 kilos. . 5856 „ 2533 kilos. 

Common salt ". ^33 L' } ' ^^'^ " ^173 „ 

For the purpose of examining the effect of common 
salt upon cereals, the General Committee of the Agricul- 
tural Society in Bavaria instituted at Bogenhausen and 
Weihenstephan, in the years 1857 and 1858, a series of 
experiments, conducted thus ; of two plots, the one was 
manured with salts of ammonia, the other with the same 
quantity of salts of ammonia and an addition of 3080 
grammes of common salt. These experiments were 
described at page 302, and it AviU be sufficient here to 
quote the crops which were obtained with salts of am- 
monia alone, and with common salt added to salts of 
ammonia. 



COMMON SALT WITH SALTS OP AMMONIA. 



337 



Bogenhausen, 1857. 



Barley 


Manm-ed with 
salts of ammonia 


Manured with 
common salt and salts of ammonia 


Corn 


Straw 


Corn 


Straw 


Plot I. . . 
„ II. . 

„ in. . . 


Grammes 
6355 
8470 
7280 
6912 


Grammes 
16205 
16730 
17920 

18287 


Grammes 

14550 

16510 

9887 

11130 


Grammes 
27020 
36645 
24832 
27969 



Bogenhausen, 1858 (p. 303). 



Winter-wheat 


Mannred with 
salts of ammonia 


Manured with 
common salt and salts of ammonia 


r 

Corn 


Straw 


r 

Corn 


Straw 


Plot! . 
„ IL 
„ IIL 
„ IV. 


Grammes 
19600 
21520 
25040 
27090 


Grammes 
41440 
38940 
57860 
65100 


Grammes 
29904 
31696 
31416 
34832 


Grammes 
61040 
71960 
74984 
74684 



In both these series of experiments, the crops of 
corn and straw were remarkably increased by the addi- 
tion of common salt ; and it is scarcely necessary to 
repeat, that such an augmentation could not possibly 
have taken place unless the soil had contained a certain 
quantity of phosphoric acid, silicic acid, potash, &c., 
capable of being brought into operation, but which with- 
out common salt was not assimilable. 

Similar experiments were undertaken by the same 
society in Weihenstephan with nitrates ; and the crops 
produced by these salts alone, and with the addition of 
common salt, per hectare, were as follows : — 



338 SALT, OTTEATE OF SODA, SALTS OF AMMOIfIA, ETC. 





WeihenstejjJicm, 


L857. — Summer hai 


'leij. 




1857 

Summer-barley 
Quantity of 
manure 

4 f Corn . 
-^t Straw . 

1858 

Winter-wheat 
(the same 
manures) 

•p J Corn 

^ t Straw . 


I. 

Unmanured 


II. 

Nitrate of 
soda 


in. 

Nitrate of 

soda with 

common salt 


IV. 

Nitrate of 
potash 


V. 

Nitrate of 

potash with 

common salt 


VI. 
&uano 


kilos. 

1604 
2580 

1699 
3030 


kilos. 
402 

2676 
4378 

1804 
3954 


kilos. 
402-1-1379 

2366 
4352 

2211 

4151 


kilos. 
473 

2064 
4219 

2248 
4404 


kilos. 
473-fl379 

2313 

4766 

2323 

4454 


kilos. 
473 

1922 
3300 

2366 
5091 



The experiments are remarkable, in so far as tliey 
appear to indicate the cases in which the nitrates alone, 
or in combination with common salt, exert a favourable 
influence upon the increase of the crops. 

The land in Weihenstephan is peculiarly suited for the 
cultivation of barley. Field A, after a manuring of the or- 
dinary kind, about 600 cwt. per hectare, had borne turnips 
in 1854, peas in 1855, and wheat in 1856 ; it was then 
intended to let it he fallow for one year, and to dress it at 
the end of the year for a new crop. On the other hand, 
Eield Bjbefore the experiment was made, had already borne 
four crops, namely, rape, wheat, clover grass, and oats ; 
and was, in comparison with the first field, more exhausted, 
and by means of the oats and clover made much poorer 
in nutritive substances for the following cereal crop. 

This seems to afford an explanation of the striking fact, 
that in 1857 the nitrates exercised upon the field a far 
more favourable influence than guano, although the soil 
had received as much nitrogen in the guano as in the 
nitrates, with the addition of phosphoric acid and potash. 
The field was still rich enough in nutritive substances for 
a good barley crop, and merely required theu- more uni- 
form distribution (which was effected by the nitrates and 
the common salt), in order to make available to the roots 



EFFECT OF COMMON SALT. 339 

of the barley plants as mucli or even more food than was 
the case with the plot manured with guano, on which the 
sum of the nutritive substances was greater. 

In estimating the results of these experiments we must 
take into account the fact established by Dr. Zoeller, that 
soda seems to take a definite part in the production of 
barley seed. It is clear that the nitrates used did not 
simply act as agents in distributing other nutritive sub- 
stances, but the soda as well as the nitric acid had their 
own share in the production of the crop. In the fourth 
experiment the field received as much nitric acid as in the 
second, but the base combined with the acid was potash 
and not soda ; and in the fifth experiment the addition of 
common salt produced a remarkable increase in the corn 
crop. However, in the third and fifth experiments the 
quantity of salt apphed was evidently too high, and the 
excess brought down the crop below that obtained with 
nitrate of soda alone. 

Upon the more exliausted field in 1858 the crop 
obtained by guano in corn and especially in straw ex- 
ceeded aU the rest. In the arable soil of this field the 
amount of nutritive substances was on the whole smaller, 
and the addition of fresh elements of food made itself felt 
in a much higher degree than the distribution or dissemi- 
nation of the substances already present in the soil. Still 
by the addition of common salt the crop of wheat was 
also increased. 

The effect of potash upon wheat is as striking as that of 
soda upon barley. 

As regards the effect of common salt and salts of soda 
generally, the analysis of the ash of turnips and potatoes, 
kitchen-garden and meadow plants, shows that, as a rule, 
the ashes of the former contain a considerable quantity of 
soda, and the ashes of the latter are proportionately rich 

z 2 



340 SALT, NITKATE OF SODA, SALTS OF AMMONIA, ETC. 

in cliloricles. The grass of a meadow, wliich has been 
manured with common salt, is eaten by cattle with greater 
relish, and preferred to any other, so that even from this 
point of view common salt deserves attention as a manure. 

As that part of the action of nitrate of soda, sea-salt, 
and salts of ammonia, which consists in effecting the dis- 
tribution in the soil of other elements of food, may con- 
sequently be replaced by careful tillage, the effect pro- 
duced upon the crops by these salts affords a pretty safe 
indication of the condition of a field. If all other circum- 
stances are the same, their effect will be much less marked 
upon a well tilled field than upon one not in the same 
condition. 

Gypsum. — Among the recent investigations respect- 
ing the action of gypsum on clover,* those made by 

* That excellent and most ably conducted agricultural journal, 
' Zeitschrift des landwirthschaftlichen Vereins fiir Ehein. Preussen/ 
contains, in Nos. 9 and 10, September and October 1861, p. 352, tlie 
following statein.ent about the remarkable fertility of a field for clover: — 

' Twenty-tliree years ago Farmer Kirfield, of Ebon, in tlie liiuidred of 
Antweiler, Aldenau district (volcanic Eifel mountains), sowed a plot of 
land, said to abound in broken shells, with esparsette. For ten years 
he obtained good hay crops, and abundant after-grass. After this time 
a good deal of grass began to make its appearance among the esparsette. 
To destroy this Mr. Kirfield had his field deeply harrowed in spring, 
with iron harrows across the ridges, and then sown over again mth 
8 pounds of red clover seed. The red clover grew up splendidly with 
the esparsette, and gave for three years running two full crops per 
annum. At the end of the third year the land was again deeply har- 
rowed and sown ancAV with 8 pounds of red clover seed. It gave 
again for three years running two full crops per annum of an excellent 
mixture of esparsette and red clover. The same operation was re- 
peated twice after with the same success, so that the field has now for 
twenty-two years, consecutively, borne clover ; that is to say, the first 
ten years esparsette alone, the following twelve years esparsette with 
red clover.' 

It would be interesting to get a j)roper analysis of this soil, with 
especial regard to its absorptive power for potash and phosphate of 
lime. 



ACTION OF GYPSUM ON CLOVEE, 341 

Dr. Pincus of Insterburg are the most important, botli on 
account of the careful manner in which they were con- 
ducted, and the conclusions drawn from them. At Dr. 
Pincus' request, three plots of ground, each of a morgen 
(about ^ of an acre) in extent, and lying close together, 
were selected by Mr. Eosenfeld in the beginning of May, 
from the middle of a la,rge clover field in the neighbour- 
hood of Lenkeningken. The clover crop had a very pro- 
mising appearance, and the plants were then about an inch 
high. One of the plots was manured with a cwt. of 
gypsum, the second with the same quantity of sulphate of 
magnesia, and the intervening plant was left unmanured. 
The clover field from which the plots were selected was 
one of the best cultivated and most fertile in the district, 
and had produced in the preceding summer an abundant 
rye crop. The plants growing on the unmanured plot, 
when compared with those on the manured, very speedily 
presented a difference of colour and condition. 

On the plot manured with gypsum, they were of a 
deeper green, and stood higher. The difference was most 
striking at the time of flowering, which occurred in the 
unmanured plots four or five days earlier than in the 
manured ; the whole field being everywhere in full bloom, 
when scarcely a flower was to be seen in the manured 
plots. When the manured plots also were in flower the 
clover was mown (May 24th). A square ruthe was mea- 
sured from each of the experimental plots, and the clover 
separately cut and weighed. 

Calculated per Prussian morgen (=f of an acre), the 

results were, Cwts. of clover-hay 

per morgen 

Without manure . . . . . 21'6 cwts. 
With gypsum ..... 30' 6 ,, 

With sulphate of magnesia . . . 32'4 ,, 

On a closer examination of the clover-hay it was fomid 



342 SALT, NITEATE OF SODA, SALTS OF AMMONIA, ETC. 

that the increase in the crops obtained from the plots 
manured with the sulphates did not extend equally to all 
parts of the plant, but was more particularly observable 
in the production of stems. There were found in 100 
parts of the clover from the manured plots more stems, 
fewer leaves, and still fewer flowers, than in 100 parts of 
the unmanured clover. 



100 parts of clovei'-Iiay, flowers . 
„ leaves . 

„ steins . 



Unmanured 

. 17-15 

. 27-45 
55-40 



or. 



Flowers 

Clover -hay, unmanured . . . 17-15 

„ manured Avith gypsum . 11*72 

„ ' ,, sulphate of 

magnesia . . .12*16 



Manured 

with, 
gypsum 

11-72 

26-22 
61-62 



Leaves 

27*45 

25-28 



Manured 

with sulphate 

of magnesia 

12-16 

25-28 
63-0 



stems 

55-40 
630 



26-22 61-62 



These proportions of the different organs of the clover 
plant show that the action of the sulphates has led to a 
very considerable increase of the wood-cells, or, in other 
words, to an extension of the stems at the expense of the 
flowers and leaves. The relative proportion of the 
flowers, leaves, and stems, was : — 





riowers 


Leaves 


stems 


Clover-hay, unmanured . 


. 100 


: 160 : 


: 323 


„ manured with gypsum 


. 100 : 


: 216 ; 


; 507 


„ „ sulphate 


of 






magnesia 


. 100 : 


: 216 : 


538 



According to the law of the symmetrical developement 
of plants, we may, without risk of error, take it for 
granted that the developement of the root increased in 
the same ratio as that of the stem. JSFow, as the increase 
of a plant in bulk is proportionate to the extent of food 
absorbent surface, we can understand that the manured plots 
should have produced when compared with the unmanured 



EFFECT OF GYPSUM ON CLOVER. 343 

not only a larger mass of stems, but, as in the case of tlie 

sulphate of magnesia plot, also of flowers and leaves. 
The entire crop, per morgen, was, — 

Manured Manured with 

Umnanured \vith sulphate of 

gypstun magnesia 

Flowers . . . 370-5 lbs. 358-5 lbs. 394-0 lbs. 

Leaves . . . 592-9 „ 773-7 „ 849-5 „ 

Stems . . . 1196-6 „ 1927-8 „ 1996-5 „ 



2160 „ 3060 „ 3240 „ 

The quantity of most of the ash constituents was found 
larger, nearly in the same proportion as the produce was 
greater. Phosphoric and sulphuric acids, however, 
showed in this respect a marked difference from the 
other ash-constituents, inasmuch as the quantity of these 
two substances was both absolutely and relatively larger 
in the clover from the manured plots. 

The ash of the air-dried clover-hay amounted to — 

Manured Manured with. 

Unmanured with sulphate of 

gypsum magnesia 

Per cent. . . . 6-95 7-96 7-94 

In the entire crop . . 150-0 lbs. 243-0 lbs. 257-0 lbs. 

Containing sulphuric acid . 2-0 „ 8*0 „ 6-0 „ 

„ phosphoric acid 11-95 „ 21-55 „ 21-82 „ 

The dressing with the sulphates had checked the deve- 
lopement of the flowers, and also that of the fruit ; and 
it is evident that, though a higher crop of stems and 
leaves may be obtained by the use of these agents from a 
given surface, the result is not the same as regards the 
seeds. With an increase of flowers, leaves, and stems in 
the same ratio as on the unmanured plot, the two mor- 
gens of ground, dressed severaUy with gypsum and 
sulphate of magnesia, ought to have produced more than 
600 lbs. of flowers each ; whereas, compared with the 



344 SALT, NITEATE OF SODA, SALTS OF AMMONIA, ETC. 

enormous increase in the weight of the stems, and a not 
inconsiderable one in the weight of the leaves, we find no 
increase of flowers, and consequently also none of seed 
(Pincus). These most carefully conducted experiments 
confirm the general rule, that wherever external causes 
favour the developement of some organs, it can only be 
effected under like conditions of the soil, at the expense 
of other organs, and that m the case of clover, as in that 
of the cereals, increase of straw is attended with decrease 
of seed. (For further details of these experiments, see 
Appendix J.) 

As the substitution of magnesia for hme, in the experi- 
ments now described, led to an increase of the clover crop, 
it may be safely assumed that in cases where gypsum is 
found to be favourable to the growth of clover, the cause 
must not be sought for in the hme, although it is very 
often found that many fields will grow clover only after a 
copious dressing with hydrate of lime. For we know 
also that gjrpsum promotes the growth of clover on many 
fields naturally abundant in hme ; and since arable soil 
has the property of absorbing ammonia from the air and 
rain-water, and fixing it in the same or even a higher 
degree than salts of hme, there is only the sulphuric acid 
left to look to for an explanation of the favourable action 
of gypsum upon the growth of clover. 

But the experiments of Pincus clearly demonstrate that 
the crops obtained by manuring with the sulphates bear 
no proportion whatever to the quantity of sulphuric acid 
supplied in them to the field. 

The quantities of sulphuric acid severally contained in 
the two sulphates used were 30T2 lbs. in the sulphate of 
magnesia, and 4448 lbs. in the sulphate of lime, which is 
as 6 : 8-8. The quantities of sulphuric acid in the two 
crops obtained severally by sulphate of lime and sulphate 



ACTION OF GYPSUM ON CLOVER NOT KNOWN. 345 

of magnesia, were as 6 : 8 ; the asli of the clover pro- 
duced by sulphate of lime contained a little more than 
8 lbs., and that from the sulphate of magnesia 6 lbs. On 
the plot dressed with gypsum the clover plant found a 
larger total quantity of sulphuric acid than on the sulphate 
of magnesia plot, and absorbed a correspondingly larger 
proportion. But this additional quantity of sulphuric 
acid absorbed did not increase the amount of produce ; 
on the contrary, on the plot manured with sulphate of 
magnesia, which had received less sulphuric acid than the 
gypsum plot, the amount of vegetable matter was 8 per 
cent, higher than on the latter. 

These facts show that we are still in the dark about the 
action of gypsum ; and it will yet require a great many 
and most accurate observations before we are hkely to 
arrive at a satisfactory explanation. 

So long as the notion was generally entertained that 
plants derived their food from a solution, the effects of a 
soluble salt upon vegetation could, of course, be attri- 
buted only to the constituents of that salt. But now we 
are aware that the earth itself performs a special part in all 
the processes of nutrition ; and there might, therefore, be 
grounds for supposing that the action of gypsum upon 
arable earth, or of the latter upon the former, might 
furnish a key, to some degree at least, to explain the effect 
of gypsum upon the growth of clover. A series of ex- 
periments made by me upon the alterations which a satu- 
rated solution of gypsum in water undergoes in contact 
with different arable soils, give very remarkable results, 
which I will now state, without venturing to draw any 
definite conclusions from them. 

I found that a solution of gypsum in contact with aU. 
the arable soils which I used, underwent decomposition, 
part of the lime separating from the sulphuric acid, and 



346 SALT, NITRATE OF SODA, SALTS OF AMMONIA, ETC. 

magnesia and potasli taking its place, quite contrary to the 
ordinary aiSnities. 

The experiments were made as follows: — 300 grammes 
of each earth were mixed with a Htre of pure water, and 
300 other grammes of the same earth with a litre of a 
saturated solution of gypsum. After twenty-four hours 
the fluid was filtered, and the filtrate tested for magnesia. 
Pure distilled water took up from all the experimental 
earths, sulphuric acid and chlorine, besides traces of lime, 
magnesia, and soda, and occasionally also of potash, but 
mostly in inappreciable quantities. The alkahes, as well 
as the lime and the magnesia, seem to be dissolved by the 
agency of organic matters, as the dried residues blackened 
upon heating, and efiervesced with acids after ignition. 

Quantities of magnesia dissolved severally out of 300 grammes of earth 
hy one litre of 



BogenhaTisen earth 
Sclileissheim „ 


• 


Distilled water 
Milligr. of magnesia 

. 30-2 
. 31-6 


G-ypsum water 
Milligr. of magnesia 

70-6 

87-8 


Bogenhausen subsoil . 


. 


. 


12-2 


84-2 


Earth from 


Botanic Gardens 




45-4 


168-6 


5> 


Bogenhausen, 

5> 


No. 
No. 


I.* 
II. 


26-6 
38-2 


101-6 
98-0 


n 


Schornhof 


. 


. 


8-6 


63-4 


J) 


a cotton field, Alabama 


1-9 


3-8 



These figures show that dressing a field with sulphate^ 
of lime makes the magnesia in the soil soluble and dis- 
tributable. If the action which gypsum exercises upon 
the growth of clover depends really upon an increased 
supply of magnesia, this must surely be looked upon as 
one of the most curious facts known, since the increased 

* On this field it had been experimentally proved that dressing Avith 
gypsum would give a larger clover crop. No. I. had not yet been 
manured with gypsum, No. II. had. 



THE ACTION OF GYPSUM IS COMPLEX. 347 

supply is effected here by tlie aid of a lime salt. An 
experiment, made specially for the purpose, showed that 
the contact of arable earth with the solution of sulphate 
of lime is attended by an actual substitution of magnesia 
for lime ; that is to say, a certain quantity of lime is with- 
drawn from the solution and combines with the earth, 
whilst the liberated sulphuric acid, which was united to 
the lime, withdraws from the earth an equivalent quan- 
tity of magnesia. In a litre of gypsum water which 
had been in contact with 300 grammes of earth from a 
wheat-field, there were found the following quantities of 
sulphuric acid, magnesia, and hme : — 





The piire gypsum 

water 
contained in 1 litre 


Tlie gypsum water which 

had been in contact 

with the earth 


Sulphuric acid 


1'170 grammes 


1-180 grammes 


Lime . 


. 0-820 „ 


0-736 „ 


Magnesia 


— 


0-074 „ 



Besides the magnesia, a certain amount of potash also 
seems to be dissolved out of the earth by aid of the 
gypsum. 

Out of 1000 grammes of earth from a wheat-field, 
there was dissolved by — 

3 litres of pure water 3 litres of gypsum water 

Potash . . . 24-3 milligr. 43-6 milligr. 

These experiments show that the action of gypsum is 
very complex, and that it promotes the distribution of 
both magnesia and potash in the ground. This much 
is certain, that gypsum exercises a chemical action upon 
the soil, which extends to any depth of it, and that in 
consequence of the chemical and mechanical modification 
of the earth particles of certain nutritive elements be- 
come accessible to, and available for, the clover plant, 
which were not so before. 

The cause of the action of a manuring agent is 



348 SALT, NITEATE OF SODA, SALTS OF AMMONIA, ETC. 

usually sought for in the composition of the plant, but I 
do not think that this is always to be rehecl upon. The 
composition of the seed of plants of wheat, for instance, 
is so constant, or varies so httle, that it is quite impossible 
to infer from the results of the analysis of the seeds 
whether the soil on which they grow abounded or was 
deficient in phosphoric acid, nitrogen, potash, &c. The 
abundance or deficiency of food in a field exercises an 
influence upon the number and weight of the seeds, but 
not upon the relative proportion of their component 
elements. Thus, for instance, Pincus found a somewhat 
larger percentage of magnesia in the unmanured clover 
than in the plants manured with the sulphates ; but 
taking the magnesia of the whole crop, the quantity of 
this substance was much larger in the latter than in the 
former. 

Amount of magnesia in — 



100 parts of asli of clover-liay . 


Unmanm-ed 

5-87 


Manured 

with 
g3Tsum 

5-47 


Manured 
with sulphate 
of magnesia 

5-27 


In the whole crop . 


8-8 lbs. 


13-29 lbs. 


13-54 lbs. 



Variations in the percentage proportions of potash, 
lime, and magnesia, may be often observed in all those 
plants in which, as in the case of tobacco, the vine, and 
the clover plant, potash may be substituted for hme, and 
vice versa. But in such cases the decrease of one body 
is invariably attended by a corresponding increase of the 
other, 

Now if gj^sum has the property ot effecting a distri- 
bution of the potash in the ground, and this is wanting 
in magnesia, more potash should be contained in the 
clover manured with gypsum than \vith sulphate of 
magnesia. According to the analysis made by Pincus, 
the ash of the clover-hay contained : — 



ACTION OF LIME. 



349 



In per cent. 



In the whole ash 



i Potash 
( Lime 
f Potash 
(Lime 



Clover 

manured mth 

gypsum 

35"37 lbs. 
19-17 „ 
85-9 „ 
46-6 „ 



Clover manured 

with sulphate 

of magnesia 

32-91 lbs. 
20-66 „ 
84-6 „ 
53-2 „ 



These figures show that the quantity of potash is 
indeed larger, and that of hme smaller, in the crop pro- 
duced by manuring with sulphate of hme than in the 
higher crop from sulphate of magnesia. 

In the clover-hay reaped from the latter plot, the defi- 
cient potash was manifestly replaced by Hme, and in the 
clover-hay from the gypsum manure plot, a certain 
amount of lime by potash. 

An investigation, made with much carefulness, and 
without the least bias, as this by Pincus, appears, among 
the frivolous and loosely-conducted researches with which 
agriculture unfortunately abounds, like a green oasis 
in a dreary desert, and is well calculated to show how 
much real knowledge remains still to be gained of the 
processes in the soil Avith respect to the nutrition of 
plants. (See ' Agriculturo-chemical and Chemical Ee- 
searches and Experiments made by Dr. Pincus, at the 
Insterburg Station for Agriculturo-chemical and Physical 
Experiments.' Gumbinnen. 1861.) 

Lime. — I have, unfortunately, never had an oppor- 
tunity of examining a soil on which a lime-dressing has 
exercised a beneficial efiect, as this substance is not used 
by farmers in the neighbourhood either of Giessen or of 
Munich. The experiments made by Kuhlmann, on mea- 
dows, in the years 1845 and 1846, seem to show that 
hme is principally useful in altering the condition of the 
soil ; but having no data before me as to the particular 
soil on which these experiments were made, I am unable 
to point out wherein this alteration consists. 



350 SALT, NITRATE OF SODA, SALTS OF AMMONIA, ETC. 



Hay crop reaped^ per hectare, 1845 and 1846. 

kilos. kilos. 

Meadow unmamired .... 11263 — 

,, manured with 300 kilos, of slaked 
lime, each year ..... 14263 Increase 3000 

„ manured with 500 kilos, of chalk 
each year 10706 Decrease 556 

It may safely be taken for granted here, that if the hme 
had acted as a nutritive element in the develop ement of 
the meadow plants, the plot manured with carbonate of 
Hme ought to have given a higher, but assuredly in no 
case an inferior crop, than the unmanured plot. But the 
very reverse is the case : the carbonate of Hme, which 
could only spread through the soil dissolved in carbonic 
acid, had an unfavourable effect ; the caustic lime, on the 
contrary, was beneficial. 

Among the Saxon experiments already so often alluded 
to, there are two of sufficient importance to deserve par- 
ticular mention here. One of these was made by 
Traeger, of Oberbobritzsch ; the other by Trager, of 
Eriedersdorf. The latter omitted to make a comparative 
experiment to show the difference between the produce 
from a plot manured with Hme, and that from an unma- 
nured plot of the same size. Instead of the latter, there- 
fore, I placed here by the side of the lime experiment, for 
the sake of comparison, another made with ground bones 
on a plot of the same size. 

Experiment at Oberhohritzsch. 
Lime manuring (110 ewts. quick lime). 



1851. Eye . 

1853. Oats . 

1852. Potatoes . 

1854. Clover-hay 


Produce per acre 
unmanured 


Produce per acre 
manured with lime 


Corn 


Straw 


Corn 


Straw 


lbs. 
1453 
1528 
9751 

911 


lbs. 
3015 
1812 


lbs. 

1812 

1748 

11021 

2942 


lbs. 
3773 
2320 



EXPERIMENTS WITH LIME. 



351 



Experiment at Friedersdorf. 
Lime manuring (same quantity as above). 



1851. Eye . 

1853. Oats . 

1852. Potatoes 

1854. Clover-liay 


Produce per acre, manured 
with 1644 lbs. ground bones 


Produce per acre 
manured with lime 


Corn 


Straw 


Corn 


Straw 


lbs. 

990 
1250 
8994 
4614 


lbs. 
3273 
2220 


lbs. 

1012 

1352 

12357 

4438 


lbs. 
3188 
2280 



Guano produced, in the year 1854, on the field at 
Oberbobritzscli, a higlier clover crop than the Hme (see 
page 266) ; but on the field at Friedersdorf it was smaller. 
616 lbs. of guano produced, at Friedersdorf, 2337 lbs., 
at Oberbobritzsch, 5044 lbs., of clover-hay. 

Experiments, in which I brought lime-water in contact 
with different samples of arable soil, have shown that the 
latter possesses a similar absorptive power for lime as for 
potash and ammonia. The earth was mixed with lime- 
water, and after remaining at rest until all alkaline reac- 
tion had disappeared, a fresh quantity of lime-water was 
then added, just sufficient to cause a feeble but permanent 
alkahne reaction. 

Ex2-)eriments on the amount of lime tahen up out of lime-water hy 
different arable soils. 





litre* of Bogenhausen earth took up . 
„ Schleissheim earth 
,, earth from Botanic Gardens 
„ subsoil from Bogenhausen . 
„ wheat soil .... 


Lime out of lime-water 


r 

grms. grains 
2-824 = 43-5 
2-397 = 37-0 
3-000=46-2 
3-288 = 50-6 
2-471=38-0 


\ 
, grms. grains 
2259 = 34788 
1917 = 29521 
2400 = 36960 
2630 = 40502 
1976 = 30430 


1 


„ from the same field after bearing 

a crop of clover . 
„ of tiu'f powder 


2-471 = 38-0 
6-301=97-0 


1976 = 30430 
5040 = 77616 



* 1 Litre = 1 cubic decimetre=61 cubic inches. 



352 SALT, NITEATE OF SODA, SALTS OF AMMONIA, ETC. 

The investigation into the alterations produced in the 
earth by the absorption of Kme, more especially as 
regards potash and sihcic acid rendered soluble, is not yet 
terminated. 



353 



APPENDICES. 



APPENDIX A (page 17). 

EXAMINATION OF BEECH-LEAVES AT DIFFERENT STAGES OF GROWTH. 
(dr. ZOELLER.) 

Beecli leaves and asparagus, their ash-constituents at different periods of 
growth — The aniyluni of the palm — Motion of sap in plants — Drain, 
lysimeter, river, and bog water, their constituents — Fontinalis antipp-etica 
from two difierent waters, ash-constituents — Vegetation of maize in 
solutions of its food — Experiments on the growth of beans in pure and 
prepared turf, results — Japanese agricultiu-e — The cultivated soil of 
the torrid zone, its exhaustibility, its manm-e — Analysis of clover by 
Pincus — Clover sickness, its cause. 

THE beech tree (fagus sylvatica), from which the leaves 
examined were gathered, stands in the Botanical Grarden of 
Munich. The leaves marked I. period were taken from the tree 
of four different sizes, on May 16, 1861. The smallest leaves a 
were just unfolded from the leaf-bud, whilst those marked cl 
were fully expanded. There were between a and d a difference 
of four days' growth. The other two sets, marked severally h 
and c, were in size and period of growth intermediate between 
a and d. The leaves of the I. period were very delicate, and of 
yellowish green colour. 

The leaves of the II. period were gathered on July 18, those 
of the III. period on October 15, 1861. The leaves of each 
period possessed among themselves the same size and firmness 
of structure. The colour of the July leaves was dark green, of 
those of October somewhat lighter. 

A A 



354 



APPENDIX A. 



The leaves of the IV. period were from the same tree, but 
had been gathered in the end of November, 1860. They had 
withered on the tree, and were quite dry. 

One hundred parts by weight of the fresh beech leaves con- 
tained : — 

I. Period 



Dry substance 
Water . 



30-29 
69-71 



b 
22-04 

77-96 



21-53 

78-47 



d 
21-52 

78-46 



II. 
Period 



44-13 
55-87 



III. 
Period 

43-23 
56-77 



One thousand fresh leaves contained, in grammes ; 



Dry substance . . . 10-01 15-90 32-63 6000 116-16 117-53 

Water 22-61 57-26 118-91 218-31 147-04 154-33 

Total weight of 1000 leaves . 32-62 73-16 151-54 278*31 263-20 271-86 

Ash of dry leaves per cent. , 4-65 5-40 5-82 5-76 7-57 10-15 



The amount of water in the air-dried leaves of the IV. 
period was 11*89 per cent. The quantity of ash left by the 
dried leaves was 8'70 per cent. 

For the ash analysis of the leaves of the period L, an equal 
number of leaves 6, c, d, were incinerated. 

One hundred parts of the ash of the leaves contained : — 





I. Period 


II. Period 


III. Period 


IV. Period 




loth Kay 


18tli July 


Idtli October 


End of Nov. 


Soda 


1861 


1861 


1861 


1860 


2-30 


2-34 


1-01 


. -if 


Potash .... 


29-95 


10-72 


4-85 


0-99 


Magnesia .... 


3-10 


3-52 


2-79 


7-13 


Lime .... 


9-83 


26-46 


34-05 


34-13 


Sesquioxide of iron . 


0-59 


0-91 


0-94 


1-10 


Phosphoric acid 


24-21 


5-18 


3-48 


1-95 


Sulphuric acid . 


* 


7f 


* 


4-98 


Silicic acid 


1-19 


13-37 


20-68 


24-37 


Carbonic acid and consti- 










tuents not determined . 
Total 


28-83 


37-50 


32-20 


25 35 


100-00 


100-00 


10000 


100-00 



* Not determined. 



ANALYSIS OF BEECH LEAVES. 



355 



Analysis of the ash of the leaves of the horse-chestmit and the wahiut tree, ly 
E. Stajtel. (^An. der Cliem. und Pharm.,^ vol. Ixxvi. p. 372.) 



Moisture in 100 parts of fresl 


Horse-chestnut 


"Walnut-tree 


Spring 


Autumn 


Spring 


Autumn 


I 








substance, dried at 212° Fahr 


82-09 


56-27 


82-15 


63-31 


Per cents of ash in the fresh sub 










stance .... 


1-376 


3-288 


1-092 


2-570 


Per cents of ash in the driec 


, 








substance 

100 parts of ash contained : 


7-69 


7-52 


7-719 


7-005 










Potash .... 


46-38 


14-17 


42-04 


25-48 


Lime .... 


13-17 


40-48 


26-86 


53-65 


Magnesia .... 


5-15 


7-78 


4-55 


9-83 


Alumina .... 


0-41 


0-51 


0-18 


0-06 


Sesquioxide of iron . 


1-63 


4-69 


0-42 


0-52 


Sulphuric acid . 


2-45 


1-69 


2-58 


2-65 


Silicic acid 


1-76 


13-91 


1-21 


2-02 


Phosphoric acid 


24-40 


8-22 


21-12 


4-04 


Chloride of potassium 
Total 


4-65 


8-55 


1-04 


1-73 


100-00 


100-00 


100-00 


99-98 



Analysis of the ash of jioxoeriny asparagus shoots, and of withered shoots 7vit7i 
rijje fruit. — Dr. Zoellee. 





I. 


II. 




^'lowering 


Autumn shoots 


Moisture in 100 parts of the fresh substance, dried 


shoots 


with ripe fruit 






at 212° Fahr 


84-34 


59-23 


Per cents of ash of the fresh substance 


0-946 


4-13 


,, „ dried ,, . . . 

100 parts of ash contain : 


6-050 


10-13 






Soda 


5-11 


5-25 


Potash 


34-40 


11-77 


Magnesia 


4-69 


3-61 


Lime 


9-07 


24-05 


Sesquioxide of iron ...... 


0-52 


0-94 


Phosphoric acid ....... 


12-54 


7-33 


Silicic acid .... .... 


1-85 


9-68 


Constituents not determined, &c. 

Total .... 


31-82 


37-37 


100-00 


100-00 



The asparagus shoots analysed came from the Botanical 
Grarden at Munich. The flowering shoots were cut close to the 
ground, on June 20, 1861 ; the autumn shoots were cut in the 
same way, from the same plant, on October 28, 1861. 

A A 2 



356 APPENDIX B. 

APPENDIX B (page 26). 

ON THE STARCH IN THE STEMS OF PALMS. 

The quantity of starch in one and the same stem differs to an 
extraordinary degree with the age of the plant, and the periods 
of flowering and fructification. 

The generation of starch will in some instances rapidly 
increase not only within the cells, but occasionally even at the 
expense of the cellular tissue. Thus, in the root-stock of Sabal 
Mexicana, an abundance of starch is sometimes found, not only 
in the interior of the cells, but also outside the latter. But 
this phenomena is most striking in the East India Sago Palms 
(lletroxylon), in which it can be clearly observed that the 
generation of starch proceeds in distinct periods, and is in inti- 
mate organic connection with the developement of the flowers 
and fruit. The Malays are in the habit of speaking of the tree 
as if it were with young at this period, during which it generates 
in its interior a large quantity of starch, forming the store of 
organic matter, out of which are to be produced, after liquefac- 
tion, new ligneous particles, and flowers, and fruit. This state- 
ment is peculiarly applicable to the Metroxylon Rumjphii Mart. 
(^Sagus gemtina Rumph.) This tree, which is a perfect che- 
mical laboratory for the preparation of starch, is monocarpous, 
that is to say, it flowers and bears fruit only once, and then dies. 
It has by that time attained a height of from 28 to 30 feet. 
The stem, which is cylindrical, and more than a foot in diameter, 
consists of a mere shell, about one and a half to two inches 
thick, of a whitish wood of no great degree of hardness. 
Within the shell is enclosed a mass of spongy tissue formed of 
interlaced fibres, the cells of which are filled with starch 
granules. In the first stage of growth, whilst the stem still 
remains unripe, if the expression may be allowed, it contains 
only an inconsiderable quantity of starch. As growth progresses, 
and the base of the leaf stalks, and the upper part of the stem 
begins to be covered with long fibrous filaments or prickles, the 
quantity of starch increases. 

The period of the greatest increase is indicated by the shed- 
ding of these prickles, and by the leaves being covered with a 



GROWTH OF THE SAGO PALM. 357 

sort of white rime, as if powdered lime had been dusted over 
them. The Malays call this stage the Maaputih, i.e. the tree 
grows white. From the apex of the stem shoots forth at this stage 
the flower-stalk, which at a later period crowns the tree like an 
immense antler, bearing thousands of flowers, which are replaced 
afterwards by spherical fruit covered with scales. When the 
flower- stalk attains a length of one foot, the tree has entered 
that stage which the Malays term Saga bonting, that is with 
young. A small quantity of the starch is now taken up for the 
formation of the woody fibre of the flower-stalks. Finally 
arrives the period which the Malays term Majang hara, i. e. the 
young comes forth. The flower-stalk at the apex of the stem 
now attains a length of four feet, but the spathes out of which 
the floral branches are to project, are not yet opened. The tree 
may pass through these three stages without any great reduction 
of the store of starch ; but at the next stage, termed Batsja 
Bang, i.e. the shoot branches out, when the flower-stalk 
measures from six to ten feet in height, and ten feet in circum- 
ference, the greater portion of the starch is formed into thick 
woody fibre, and still more is this the case in the two last stages 
of the flower (Siriboa) and fruit (Balioa), when there remains 
no longer any starch. A healthy tree produces between 400 
and 800 lbs. of starch (the sago prepared from this is not sent 
to the European markets, but is consumed in the country). 
The palm, which produces the chief portion of the sago con- 
sumed in Europe, is the Metroxylon laeve Mart, of Malacca, the 
wild stems of which give four to five and a half picols of sago, 
whilst two to three picols only are obtained from those cultivated 
in gardens. 



APPENDIX C (page 54). 

VEGETABLE STATICS, LONDON, 1727. 

The experiments made by Hales on the motion of the sap in 
vegetables, may be looked upon as the best model for all times 
of the most perfect method of investigation. That they are 
still at the present day unsurpassed in vegetable physiology may, 
perhaps, be attributed to the circumstance of their dating from 



358 APPENDIX C. 

the age of Newton. They deserve a place in every work treat- 
ing of the physiology of plants. 

In the beginning of his work Hales describes the experiments 
made by him on the motion of the sap in vegetables arising 
from the exhalation from their surface. These experiments 
were made with leafy branches, plants cut off from the roots, 
and others ^till retaining their roots. 

The force of the pressure of a column of water, both with 
and Avithout the cooperation of exhalation, was shown by the 
following experiment. 

He fixed an apple-branch, three feet long, half-inch in diameter, 
full of leaves and lateral shoots, to a tube seven feet long, and 
five-eighths of an inch in diameter. He filled the tube with 
water, and then immersed the whole branch up to the lower end 
of the tube, in a vessel full of water. The water was driven 
into the branch by the pressure of the column of water in the 
tube, which subsided fourteen and a quarter inches in two 
days. 

On the third day he removed the branch and tube out of the 
water, and hung it up in the open air ; the v/ater in the tube fell 
now twenty-seven inches in twelve hours. 

To determine the comparative force with which the water is 
driven through the vessels of the ligneous body by pressure alone, 
and by pressure and exhalation combined. Hales joined a leafy 
apple branch to a tube nine feet long filled with water. In 
consequence of the pressure of the column of water and of the 
exhalation taking place from the surface of the leaves and 
twigs, the water in the tube (fortieth experiment) sank 36 inches 
in an hour. He then cut off the branch 13 inches below the 
glass tube, and placed the cut portion (with leaves and twigs) 
upright in a vessel with water. It was found to imbibe 1 8 ozs. 
of water in 30 hours ; in which time only 6 ozs. of water had 
passed through the 13 inches of the stem connected with the 
tube, and that too under the pressure of a column of water 
7 feet high. 

In three other experiments, Hales shows that though the 
sap-vessels of plants will imbibe water plentifully by capillary 
attraction in branches severed from the trunk, as well as in 
those left in connection with the uninjured roots, they have 



HALES EXPEEIMENTS ON THE MOTION OP THE SAP. 359 

very little power to protrude sap out at their extremities, and 
make it rise in a tube fixed to them. 

The motion of the sap. Hales concludes, is to be attributed 
to the exhalation from the surface alone, and he proves that it 
proceeds in an equal degree from the trunk, branches, leaves, 
flower and fruit, and that the effect of the exhalation bears 
a certain definite ratio to the temperature and moisture of the 
air. T\Tien the atmosphere was charged with humidity little 
water was imbibed, and on rainy days the absorption was barely 
perceptible. Hales opens this second chapter of his statics 
with the following introductory remarks : — 

' Having in the first chapter seen many proofs of the great 
quantity of liquid imbibed and perspired by vegetables, I pro- 
pose in this to inquire with what force they do imbibe moisture. 

' Though vegetables (which are inanimate) have not an 
engine which by its alternate dilatations and contractions does in 
animals forcibly drive the blood through the arteries and veins, 
yet has nature wonderfully contrived other means, most power- 
fully to raise and keep in motion the sap.' 

In his twenty-first experiment he laid bare one of the chief 
roots of a thriving pear-tree at a depth of 2^ feet, cut off the 
end of the root, and connected the remaining stump with a 
glass tube filled vdth water and confined by mercury. This 
glass tube represents the root leng-thened. 

By the perspiration from the surface of the tree, the root 
imbibed the water in the tube with such vigour that in six 
minutes the mercury had risen in the tube as high as 8 inches, 
which corresponds to a column of water 9 feet in height. 

This force is very nearly equal to that with which the blood 
moves in the great crural artery of a horse. 'I found,' says 
Hales, in his thirty-sixth experiment, * the force of the blood 
of several animals, by tying them down alive upon their backs, 
then laying open the great crural artery where it first enters 
the thigh, and fixing to it, by means of two brass pipes running 
one into the other, a glass tube above ten feet long and one- 
eighth of an inch in diameter. In this tube the blood of one 
horse rose eight feet three inches, and the blood of another 
horse eight feet nine inches ; the blood of a little dog, six 
feet and a half.' 



360 APPENDIX C. 

Hales proved, by special experiments, that the force of 
suction shown by him to be possessed by the roots of plants, is 
exercised equally by every individual branch, shoot, leaf, and 
fruit, in short, by every portion of the surface ; that the 
motion of the sap from the root to the branches and leaves 
continues even when the trunk is, in any part, completely 
stripped of the outer and inner bark, and that this force of 
suction acts not only from the roots towards the top, but also 
from the latter towards the roots. 

He concludes, from the results of his experiments, that every 
part of the plant is endowed with a powerful force of attraction. 

We know now that it was not this force of attraction in itself 
that made the mercury and the water rise in Hales' tubes ; 
and his experiments clearly show that the imbibing force of 
plants, and of every leaf and root-fibre, arising from surface 
exhalation, is aided by a powerful force from without, which is 
simply atmospheric pressure. 

By the evaporation of the water from the surface of plants 
a vacuum is created therein, and in consequence thereof water 
and gases soluble in that fluid are readily forced in from without 
and raised by the pressure of the atmosphere, and it is this pres- 
sure from without which, together with capillary attraction, con- 
stitutes the principal cause of the motion and diffusion of the sap. 

That the surface of plants possesses the faculty of imbibing 
gases, is most conclusively demonstrated by Hales. In his twenty- 
second experiment he says : — ' The height to which the mercury 
rose in the tube did in some measure show the force with which the 
sap was imbibed, though not nearly the whole force ; for while 
the water was imbibing, the transverse cut of the brancli was 
covered with innumerable little hemispheres of air, and many 
air-bubbles issued out of the sap-vessels, which air did in part 
fill the tube as the water was drawn out of it ; so that the 
height of the mercury could only be proportionable to. the 
excess of the quantity of water drawn off, above the quantity 
of air which issued out of the wood. 

' And if the quantity of air, which issued from the wood 
into the tube, had been equal to the quantity of water imbibed, 
then the mercury would not have risen at all, because there 
would have been no room for it in the tube. 



HALES EXPEEIMENTS. 361 

' But if nine parts in twelve of the water be imbibed by the 
branch, and in the meantime but three such parts of air issue 
into the tube, then the mercury must needs rise near six inches, 
and so proportionately in different cases.' 

When, in Hales' experiments, the root, the stem, or a branch 
had been wounded in any part by cutting off root-fibres, or 
buds, or smaller twigs, the imbibing power was found to be 
diminished in the other parts (because at those wounded spots 
the difference in the pressure was more readily equalised by 
air finding its way in). The imbibing power was greatest about 
fresh cuts, but it gradually diminished until, after a few days, 
it remained no stronger about the cut than about the uninjured 
parts. Hales further concludes the exhalation from the surface 
to be the powerful cause that conveys nutriment to the plant 
from the parts surrounding it. If the proper proportion 
between the exhalation and the supply of food is in any way 
disturbed, the plant sickens and dies. If, in hot summers, the 
soil is unable to supply to the roots the moisture carried off in 
the course of the day by exhalation from the leaves, &c., and 
the tree or a branch of it is dried up, the motion of the sap 
ceases in such parts. Once dried up, the original action cannot 
be restored by capillary attraction alone. Exhalation is the 
chief condition of the life of the plant, serving, as it does, to 
effect and maintain a continual motion of the sap, and a con- 
stantly recurring change in its condition. 

' By comparing,' says Hales, ' the surface of the roots of a 
plant with the surface of the same plant above ground, we see 
the necessity of cutting off many branches from a transplanted 
tree. Suppose upon digging the plant up, in order to trans- 
plant it, half the roots be cut off (which is the case of most 
3^oung transplanted trees), then it is plain that but half the 
usual nourishment can be carried up through the roots, and 
that accordingly the perspiring surface above ground must be 
correspondingly reduced in order to restore the proper propor- 
tion between it and the imbibing surface under ground.' In 
the following observations on hop-vines. Hales shows the effect 
of suppressed perspiration : — 

' The soil of an acre of ground on which 9000 hop-vines 
are growing, must supply to the plants, through the roots, in 



362 APPENDIX C. 

July, 36,000 ozs. of water in twelve hours. This is the quantity 
of water which during this time is exhaled by them, and which 
they must have to be in a thriving condition. 

* In a kindly state of the air, this moisture is daily carried 
off in sufficient quantity to keep the hops in a healthy state ; 
but in a rainy moist state of air, without a due mixture of dry 
weather, too much moisture hovers about the hops, so as to 
hinder, in a great measure, the kindly perspiration of the leaves, 
whereby the stagnating sap corrupts, and breeds mould. 

' This was the case in the year 1723, when ten or fourteen 
days almost continual rains fell, about the latter half of July, 
after four months' dry weather ; upon which the most flourishing 
and promising hops were all infested with mould in their leaves 
and fruit, while the then poor and unpromising hops escaped, 
and produced plenty ; because they being small, did not perspire 
so great a quantity as the others ; nor did they confine the per- 
spired vapour so much as the large thriving vines did in their 
shady thickets. 

' This rain on the then warm earth made the grass shoot out 
as fast as if it were in a hot-bed ; and the apples grew so pre- 
cipitately, that they were of a very fleshy constitution, so as to 
rot more remarkably than had ever been remembered. 

^ The planters observe that when mould has once seized any 
part of the ground, it soon runs over the whole, and that the 
grass and other herbs under the hops are infected with it; pro- 
bably because the small seeds of this quick growing mould, 
which soon come to maturity, are blown over the whole ground ; 
which spreading of the seed may be the reason why some 
grounds are infected with fen for several years successively. 

' I have,' says Hales, ' in July (the season for fire-blasts, as the 
planters call them), seen the vines in the middle of a hop 
ground all scorched up, almost from one end of a large ground 
to the other, when a hot gleam of sunshine has come immedi- 
ately after a shower of rain ; at which time the vapours are often 
seen with the naked eye, but especially with reflecting telescopes, 
to ascend so plentifully as to make a clear and distinct object 
become immediately very dim and tremulous. Nor was there 
any dry gravelly bed in the ground, along the course of this 
scorch. It was, therefore, probably owing to the much greater 



HALES EXPERIMENTS. 363 

quantity of scoi'ching vapours in the middle tlian outside of the 
ground, and that being a denser medium, it was much hotter 
than a more rare medium. 

' The gardeners about London have, to their cost, too often 
had occasion to observe a similar effect, when they have incau- 
tiously put bell-glasses over their cauliflowers early on a frosty 
morning, before the dew was evaporated off them ; which dew 
being raised by the sun's warmth, and confined within the glass, 
did then form a dense transparent scalding vapour, which burnt 
and killed the plants.' 

These observations translated into the language of the present 
day clearly show how acutely and exactly Hales comprehended 
the influence of perspiration upon the life of plants. 

According to him, the proper thriving of plants depends 
upon the supply of food and moisture from the soil, which 
again is governed in a measure by a certain temperature and 
dryness of the atmosphere. The imbibing power of plants, — 
the motion of the sap in them, — is dependent upon exhalation ; 
the quantity of food imbibed and needed for the functions of the 
plant, is proportionate to the quantity of moisture exhaled in a 
given time. If the plant has imbibed a maximum of fluid, and 
the exhalation is hindered by a low temperature, or by long- 
continued wet weather, the supply of food, or the nutrition of 
the plant stops, the sap stagnates, and an alteration ensues 
tending to the generation of parasitical microscopic growths. 
If rain falls after hot weather, followed by a strong heat without 
wind, and every part of the plant is surrounded with an atmo- 
sphere saturated with moisture, cooling by further exhalation 
ceases, and the plants succumb to the sun-blasts. 



APPENDIX D (page 91). 

ANALYSES OF DEAINAGE, LTSIMETER, EIVER, AND MAESH WATEE. 

I. — Drainage Water. 

Thomas Way found in drainage water taken from seven dif- 
ferent fields, the following constituents (' Journal of the Eoy. 
Agric. Soc.,'vol. xvii. 133): — 



364 



APPENDIX D. 



Potash .... 


Grains in 1 Gallon =10,000 grains of water 


1 


2 


3 


4 


5 


6 


7 


trace 


trace 


0-02 


0-05 


trace 


22 


trace 


Soda . < . . . 


1-00 


2-17 


2-26 


0-87 


1-42 


1-40 


3-20 


Lime ..... 


4-85 


7-19 


6-05 


2-26 


2-52 


5-82 


1300 


Magnesia .... 


0-68 


2-32 


2-48 


0-41 


0-21 


0-93 


2-50 


Sesquioxide of iron and 
















alumina .... 


0-40 


0-05 


0-10 


— 


1-30 


0-35 


0-50 


Silicic acid .... 


0-95 


0-45 


0-55 


1-20 


1-80 


0-65 


0-85 


Chlorine .... 


070 


1-10 


1-27 


0-81 


1-26 


1-21 


2-62 


Sulphuric acid . 


1-65 


5-15 


4-40 


1-71 


1-29 


3-12 


9-51 


Phosphoric acid . 


trace 


0-12 


trace 


trace 


0-08 


0-06 


0-12 


Ammonia .... 


0-018 


0-018 


0-018 


0-012 


0-018 


0-018 


0-006 



Very similar results were obtained by Dr. Krocker in his 
analyses of drainage water from Proskau. (See Liebig and 
Kopp's ' Jahresbericht ' for 1853, page 742.) 







Drainage Water (in 10,000 parts) 


Organic matter .... 


a 


b 


c 


d 


e 


/* 


0-25 


0-24 


0-16 


0-06 


0-63 


0-56 


Carbonate of lime 




0-84 


0-84 


1-27 


0-79 


0-71 


0-84 


Sulphate of lime 




2-08 


2-10 


1-14 


0-17 


0-77 


0-72 


Nitrate of lime . 




0-02 


0-02 


0-01 


0-02 


0-02 


0-02 


Carbonate of magnesia 




0-70 


0-69 


0-47 


0-27 


0-27 


0-16 


Carbonate of protoxide of iron 




0-04 


0-04 


0-04 


0-02 


0-02 


0-01 


Potash .... 




0-02 


0-02 


0-02 


0-02 


0-04 


0-06 


Soda .... 




0-11 


0-15 


013 


0-10 


0-05 


004 


Chloride of sodium . 




0-08 


0-08 


0-07 


0-03 


0-01 


0-01 


Silica .... 




0-07 


0-07 


0-06 


0-05 


06 


0-05 


Total solid n 


latter 


4-21 


4-25 


3-37 


1-53 


2-58 


2-47 



* a. Drainage water from land A (a clay soil resting on a subsoil of calcareous 
loam or clay), collected 1st April, 1853. — b. The same, collected 1st May, 1853, 
after a heavy fall of rain (218 cubic inches on the square foot). — c. Drainage ■n-ater 
from the same soil, mixed with drainage water from a humous clay soil, with 
calcareous clay or loam as subsoil, collected in October 1853. — d. Drainage water 
from land B (tile-drained ; subsoil of calcareous clay or loam), collected in October 
1853. — e. Water passing through the water-furrows from a heavy clay soil, collected 
in the beginning of June.—/. The same, collected in the middle of August, after 
heavy rains. 



LYSIMETEE WATER. 



365 



II. — Lysimeter Water. 
Lysimeter water is atmospheric water passed by means of 
suitable apparatus (Lysimeter) through different soils, and col- 
lected after passing through. (See page 92.) 

The chemical analyses embraced four series, and were made 
by Dr. Zoeller. 

1. — Series of analyses made in 1857. 

The experiments were made with five different soils, 1 square 
foot of each earth, 6 inches deep, being placed in the several 
lysimeters. The quantities given represent the amount of 
atmospheric water that passed through the several lysimeters 
from April 7 to October 7, 1857. I. Manured calcareous soil, 
with vegetation (barley). II. Unmanured clay soil, with vege- 
tation. III. Unmanured clay soil, without vegetation. IV. 
Manured clay soil, without vegetation. V. Manured clay soil, 
with vegetation. (2 lbs. cattle-dung, without straw, were seve- 
rally used to manure the earth in lysimeters I., IV., and V.) 







I. 


II. 


III. 


IV. 


V. 




cub. cent. 


cub. cent. 


cub. cent. 


cub. cent. 


cub. cent. 


Quantity of water passec 












through soil in lysimeter 


9845 


18575 


18148 


19790 


12302 




grammes 


grammes 


grammes 


grammes 


grammes 


Solid residue left at 212° F 


4-651 


4-73 


5-291 


6-04 


3-686 


Ash of solid residue . 
Potash 


3-127 
0-064 


3-283 
0-044 


3-545 


4-245 


2-610 


0-037 


0-108 


0-047 


Soda . 




0-070 


0-104 


0-135 


0-470 


0-074 


Lime . 




1-436 


1-070 


1-285 


1-354 


1-136 


Magnesia . 




0-203 


0-165 


0-024 


0-058 


0-063 


Sesquioxide of iron 




0-013 


0-119 


0-150 


0-114 


0-053 


Chlorine . 




0-566 


0-177 


0-379 


0-781 


0-434 


Phosphoric acid 




0-022 


trace 


trace 


trace 


trace 


Sulphuric acid . 




0-172 


0-504 


0-515 


0-580 


0-412 


Silicic acid 




0-103 


0-210 


0-317 


0-188 


0-115 


Clay and sand . 




0-089 


0-074 


0-112 


0-045 


0-047 


Total 


2-738 


2-467 


2-954 


3-698 


2-381 


Deduct equivalent of oxygen 












corresponding to chlorine 
Balance . 


0-127 


0-040 


0-085 


0-176 


0-095 


2-611 


2-427 


2-869 


3-522 


2-286 


Carbonic acid and loss 


2-040 


2-303 


2-422 


2-518 


1-400 


Total 




4-651 


4-730 


6-291 


6-040 


3-686 



366 



APPENDIX D. 



1,000,000 litres of water, passed througli 6 inches of the soils 
already described, contain — 









I. 


II. 


III. 


IV. 


V. 




grammes 


grammes 


grammes 


grammes 


grammes 


Solid residue left at 212° F 




472-32 


254-64 


292-64 


305-20 


291-50 


Ash contained in it 
Potash 






317-62 


176-74 


194-78 


214-50 


212-16 


6-50 


2-37 


2-03 


5-46 


3-82 


Soda . 






7-11 


5-60 


7-43 


23-74 


6-02 


Lime 






145-86 


57-60 


70-80 


68-41 


92-34 


Magnesia . 






20-52 


8-88 


1-32 


2-93 


5-12 


Oxide of iron 






1-32 


6-35 


8-26 


6-76 


4-30 


Chlorine . 






57-49 


9-52 


20-87 


39-46 


35-27 


Phosphoric acid . 






2-23 


— 


— 


— 




Sidphm-ic acid . 






17-47 


27-13 


27-82 


29-30 


33-49 


Silicic acid (soluhle) 






10-46 


11-35 


17-46 


9-50 


9-34 



2. — Series of analyses made in 1858. 

The waters analysed were obtained from six soils, and repre- 
sent the quantity of atmospheric water that passed, from May 10 
to Nov. 1, 1858, through a layer of earth of a square foot of 
surface and 12 inches deep. The earth was ordinary unma- 
nured alluvial lime soil from the Isar. The plant selected for 
cultivation was the potato. I. Unmanured, and without vege- 
tation. II. Unmanured, with vegetation. III. Manured, 
10 grammes common salt, with vegetation. lY. Manured, 
10 grammes nitrate of soda, with vegetation. V. 10 grammes 
guano, with vegetation. VI. Manured, 20 grammes phos- 
phorite made soluble with hydrochloric (?) acid, with vegeta- 
tion. 



LYSIMETER WATER. 



367 







I. 


II. 


III. 


IV. 


V. 


VI. 




cub. cent. 


cub. cent. 


cub. cent. 


cub. cent. 


cub. cent. 


cub. cent. 


Quantity of water passec 














through the soil 


29185 


25007 


28138 


17466 


16520 


30850 




grammes 


grammes 


grammes 


grammes 


grammes 


grammes 


Solid residue left at 212° F 


8-985 


8-214 


14-198 


7-681 


4-864 


8-001 


Ash of the soUd residue 
Soda .... 


6-591 


6-094 


12-292 


5-553 


3-704 


6-192 


0-250 


0-245 


3-290 


1-255 


0-301 


0-233 


Potash 




0-075 


0-066 


0-034 


0-035 


0-032 


0-029 


Magnesia . 




0-432 


0-443 


0-454 


0-264 


382 


0-374 


Lime 




2-416 


2-467 


2-356 


1-792 


1-378 


2-645 


Oxide of iron 




0-115 


0-083 


0-104 


0-083 


0-096 


0-117 


Chlorine . 




0-227 


0-237 


3-925 


0-177 


0-317 


0-238 


Phosphoric acid 




trace 


trace 


0-009 


trace 


0-007 


0-015 


Nitric acid 




— 


— 


— 


3-267 


— 


— 


Sulphm-ic acid . 




0-132 


0-147 


0-118 


0-182 


0-197 


0-666 


Silicic acid 




266 


0-301 


0-384 


0-303 


0-226 


0-2-24 


Sand 




0-155 


0-237 


0-155 


0-105 


0062 


0083 


Sum 


4 068 


4-226 


10-829 


7-463 


2-998 


4-644 


Less the amount of oxygen 














equivalent to.the chlorine 
Sum 


0-051 


0-053 


0-884 


0-039 


0-071 


0-053 


4-017 


4-163 


9-945 


7-424 


2-927 


4-591 


Loss and carbonic acid 


4-968 


4-051 


4-253 


0-257 


1-937 


3-410 


Sum 


• 


8-985 


8-214 


14-198 


7-671 


4-864 


8-001 



1,000^000 litres of water, passed through 10 inches of the 
soils already described, contain — 









I. 


II. 


III. 


IV. 


V. 


VI. 




grms. 


grms. 


grms. 


grms. 


grms. 


grms. 


Solid residue left at 212°P. 


307-86 


328-46 


504-58 


439-76 


294-42 


259-35 


Ash contained in it 
Soda .... 


225-83 


243-69 


436-84 


374-04 


224-21 


200-71 
7-55 


8-56 


9-79 


.116-92 


71-85 


18-22 


Potash . 






2-56 


2-63 


1-20 


2-00 


1-93 


0-94 


Magnesia 






14-80 


17-71 


16-13 


15-11 


23-18 


12-12 


Lime 






82-78 


98-65 


83-73 


102-59 


83-41 


85-73 


Oxide of iron 






3-94 


3-31 


3-69 


4-75 


5-81 


3-79 


Chlorine 






7-77 


9-47 


139-49 


10-13 


1918 


7-71 


Phosphoric acid 






— 


— 


0-31 





0-42 


0-48 


Nitric acid 






— 


— 


— 


187-04 


— 


— 


Sulphuric acid 






4-52 


5-87 


4-19 


10-42 


11-09 


21-59 


Silicic acid 






9-11 


12-03 


13-64 


17-34 


13-68 


7-26 



368 



APPENDIX D. 



3.- -Series of analyses made in 1859. 

The waters analysed were obtained from six soils, and repre- 
sent the quantity of atmospheric water that passed from March 20 
to Nov. 16, 1859, through a layer of earth of a square foot of 
surface and 12 inches deep. The earth was ordinary unmanured 
alluvial lime soil from the Isar (garden soil). All the soils 
were in grass. I. Unmanured. II. Manured, 17*8 grammes 
nitrate of potash. III. Manured, 15*4 grammes sulphate of 
potash. IV. Manured, 17*8 grammes nitrate of potash, and 
3 '6 6 grammes phosphoride made soluble with 2 grammes sul- 
phuric acid. V. Manured, 15 "4 grammes sulphate of potash, 
and 3*66 grammes of phosphorite made soluble as above. VI. 
Manured, 12*3 grammes carbonate of potash. 







I. 


II. 


III. 


IV. 


V. 


VI. 




cubic 


cubic 


cubic 


cubic 


cubic 




Quantity of water pass 


ed cent. 


cent. 


cent. 


cent. 


cent. 


cent. 


through the soil . 


20201 


14487 


20348 


17491 


23205 


22488 




grammes 


grammes 


grammes 


grammes 


grammes 


grammes 


Solid residue left at 212° 


P. 4-5631 


11-4272 


15-1967 


13-6805 


20-784 


5-5878 


Ash of the solid residue 
Soda 


3-192 


8-861 


13-644 


10-681 


17-668 


4-614 


0-044 


0-069 


0-083 


0-030 


0-085 


0-038 


Potash . 




0-024 


0-166 


0-205 


0-231 


0-244 


0-112 


Magnesia 




0-253 


0-302 


0-296 


0-285 


0-320 


0-117 


Lime 




1-530 


3-483 


5-360 


4-838 


7-112 


1-963 


Oxide of iron 




0-072 


0-057 


0-072 


0-084 


0-088 


0-053 


Chlorine 




0-035 


0-080 


0-202 


0-132 


0-283 


0-127 


Phosphoric acid 




trace 


trace 


trace 


trace 


trace 


trace 


Sulphuric acid 




0-289 


0-205 


6-527 


2-104 


9-124 


1-524 


Nitric acid 




1-125 


5-913 


1-301 


5-248 


1-401 


1-390 


Silicic acid 




0-178 


0-271 


0-208 


0-230 


0-280 


0-269 


Sand . 




0-044 


0-021 


0-036 


0-025 


0-056 


0-097 


Sum 


3-594 


10-567 


14-290 


13-207 


18-993 


4-690 


Less the amount of oxygt 


>n 












equivalent to the chlori 
Sum 


lie 0-007 


0-018 


0-045 


0-029 


0-063 


0-028 


3-587 


10-549 


14-245 


13.178 


18-930 


4-662 


Loss and carbonic acid , 


0-9761 


0-8782 


0-9517 


0-5025 


1-854 


0-9258 


Sum 




4-5631 


11-4372 


15-1967 


13-6805 


20-784 


5-5878 



1,000,000 litres of water, passed through 1 foot of the soils 
already described, contain — 



LTSIMBffER WATEE. 



369 









I. 


11. 


III. 


IV. 


V. 


VI. 




grammes 


grammes 


grammes 


grammes 


grammes 


grammes 


Solid residue left at 212° F. 


225-38 


788-78 


746-84 


782-14 


895 66 


248-48 


Ash contained in it 
Soda 




158-0 


611-64 


670-52 


610-65 


761-36 


205-17 


2-17 


4-76 


4-07 


1-71 


3 66 


1 68 


Potash . 






1-18 


11-45 


10-07 


13-20 


10-51 


4-98 


Magnesia 






12-52 


20-84 


14-54 


16-29 


13-79 


5-20 


Lime 






75 73 


240-42 


263-41 


276-59 


306-48 


87-29 


Oxide of iron . 






3-56 


3-93 


3-53 


4-80 


3-79 


2-35 


Chlorine 






1-73 


5-52 


9-92 


7-54 


12-19 


5-64 


Sulphuric acid 






14-30 


1415 


320 76 


120-29 


393-19 


23-30 


Nitric acid 






55-69 


408-15 


63-93 


300^04 


60-37 


61-76 


Silicic acid 






8-81 


18-70 


10-32 


13-14 


12-06 


11-96 



4. — Series of analyses riiade in 1859, 1860. 
This series is a direct continuation of the third. The waters 
analysed passed through the same soils through which the 
waters of the third series had already passed. The fourth series of 
experiments continued from Nov. 16, 1859, to Aj)ril 12, 1860. 



Quantity of water passed 
through the soil 


I. 


II. 


III. 


IV. 


V. 


VI. 


cubic 

centimtrs. 

13500 


cubic 

centimtrs. 

12332 


cubic 

centimtrs. 

13760 


cubic 

centimtrs. 

13150 


cubic 

centimtrs. 

15232 


cubic 

centimtrs 

14850 


Solid residue left at 


grammes 


grammes 


grammes 


grammes 


grammes 


grammes 


212° Fahr. . 


2-424 


2-205 


2-860 


2-640 


3-172 


2-691 


Ash of the soUd residue 
Soda 


2-071 


1-682 


2-395 


2-086 


2-599 


2-220 


0-021 


0-024 


0-028 


0-022 


0-028 


0-019 


Potash . . V 


trace 


0008 


0-012 


0-009 


0-015 


O-Olo 


Magnesia . 


0-065 


0-058 


0-069 


0-074 


0-070 


063 


Lime 


0-770 


0-859 


1-016 


0-938 


0-952 


1-057 


Oxide of iron 


0-061 


0-066 


0-097 


075 


0-135 


0-049 


Chlorine . 


01^0 


0042 


0-093 


0-068 


0-091 


0-084 


Phosphoric acid 
Nitric acid 


trace 
0-025 


trace ' 
0-101 


trace 
0-043 


trace 
0-077 


trace 
029 


trace 
0-046 


Sulphuric acid . 
Silica and sand * 

Sum 


0-119 
0-170 


0099 
0-144 


0-487 
0-118 


0-474 
0-153 


0-527 
0-123 


0-185 
0-136 


1-371 


1-401 


1-963 


1-890 


1-970 


1-654 


Deduct the amount of 














oxj'gen equivalent to 
the chlorine . 

Sum 


0024 


0-009 


0-020 


0-015 


0-020 


0-018 


1-347 


1-392 


1-943 


1-875 


1-950 


1-636 


Loss and carbonic acid 
Sum 


1-077 


0-813 


0-917 


0-765 


1-222 


0-955 


2-424 


2-205 


2-860 


2-640 


3-172 


2-691 



* The quantity of sand very small. 
B B 



370 



APPENDIX D. 



1,000,000 litres of water, passed through 10 inches of the 
soils already described. 









I. 


II. 


III. 


IV. 


V. 


VI. 


Solid residue left at 


grammes 


grammes 


grammes 


grammes 


grammes 


grammes 


212° Fahr. . 


179-56 


178-80 


207-71 


200-81 


208-24 


181-21 


Ash contained in it 
Soda 


153-47 


136-39 


174-07 


158-69 


170-62 


149-49 


1-56 


1-94 


2-04 


1-73 


1-83 


1-27 


Potash . 






— 


0-64 


0-92 


0-69 


0-98 


1-01 


Magnesia . 






4-86 


4-70 


5-02 


5-56 


4-59 


4-24 


Lime 






57-04 


69-49 


73-87 


71-39 


62-50 


71-17 


Oxide of iron 






4-52 


5-35 


7-06 


5-73 


8-86 


3-29 


Clilorine . 






10-43 


3-40 


6-76 


5-21 


5-97 


5-65 


Nitric acid 






1-91 


8-19 


3-17 


5-91 


1-90 


3-09 


Sulphuric acid 






8-86 


8-02 


35-45 


36-08 


34-59 


12-45 


Silicic acid with a little 














sand 


12-60 


11-67 


8-60 


11-65 


8-01 


9-15 



Compare ' Annal der Chem. und Phar.,' bd. 107, s. 27 ; 
* Ergebnisse landwirthsch. und Versuche der Versuch station, 
Miinchen,' II. Heft, s. 65, und III. Heft, s. 82. 



Analysts of ashes of plants fi'om the rivers Ohe and Iser, — De. Wittsteest. 





Fontinalis 


Antipvretica * 


Chloride of sodium ...... 


from the Olie 


fi-om the Iser 


0-346 


0-834 


Potash 

Soda . . . : 












0-460 
1-745 


1 2-325 


Lime 












2-755 


18-150 


Magnesia , 












1-133 


5-498 


Alumina . 












9-272 


1-616 


Oxide of iron 












17-039 


9-910 


Oxide of manganese . 












4-555 


0-850 


Sulphiu'ic acid . 












1-648 


2-827 


Phosphoric acid 












trace 


5-962 


Silicic acid 












61-000 


51-494 


Carbonic acid . 














— 


Sum 












99-953 


99-466 



* The great difference in the composition of the ashes of one and the same plant 
arises, according to Dr. Niigeli, less perhaps from the different amoimt of these 
matters in the water than from difference of age in the plants, and probably more 
still from other plants which nestle in the moss. 



EIVER WATEE. 



371 



^ 



|3oa 



£ O C 



f^.^: 






! 






,o Q 











[■^-^ -^ 





t^ 


10 


CO 


CO 


GO 


1>- 


KD 





00 


,—1 







CO 





<n 


lO 




co 




CO 


CO 







s 9S 


CO 


(M 


!M 


C5 





»— ' 


(M 


I— ' 


CO 


(M 


CD 


.a 


Z,""^ 





,__( 


CO 


!N 


T_l 








r-{ 


CO 


t^ 


CO 


o 


(S°a 






















t^ 


-a 


























^\ 


s 


'O 


00 


(M 


CO 


10 


t^ 


t^ 


(M 


>o 


^ 







-i 


!M 


05 


CO 


CO 


CO 


r-H 


CO 


00 


(M 


CO 











(M 


^ 










1— i 


lO 


,— ( 


10 






























1—1 






i-H C3 
































T-H 




. Ed 




































O PM 



:^ g ^ 



B B 2 



372 



APPENDIX D. 



IV. — Moss ivaterfrom the neighbourhood of Schleissheim. — 
Dk. Wittstein. 

The composition of the water was found to be as follows : — 



Chloride of sodium 

Potash 

Soda ....... 

Lime ....... 

Magnesia ....... 

Ahimina ....... 

Oxide of iron ...... 

Sulphuric acid ...... 

Phosphoric acid ..... 

Silicic acid ...... 

Carbonic acid ...... 

Organic matter ...... 

Total amount of solid matter 
Total amount of inorganic matter 



In 1000 grammes 


In 100 parts of 


of water 


solid matter 


0-00280 


1-101 


0-00022 


0-086 


0-00551 


2-167 


0-05266 


20-723 


0-00921 


3-627 


000029 


0-114 


0-00197 


0-775 


000372 


1-466 


0-00002 


0-008 


0-00069 


0-271 


0-03943 


15-595 


0-13771 


54-067 


0-25423 


100-000 


0-11652 





APPENDIX E (page 108). 



VEGETATION OF LAND PLANTS IN THE WATERY SOLUTIONS OF 

THEIR FOOD. 



In experiments on the vegetation of land plants in the watery 
solutions of their food, great attention must be paid to the ten- 
dency of the fluid to become alkaline by the process of vegeta- 
tion, as land plants always die in alkaline solutions. Grreat care 
must therefore be taken to keep the fluid neutral (very faintly 
alkaline) or feebly acid. Knop attained this object by fre- 
quently transferring his plants to fresh solutions ; Stohmahn, by 
placing the plants from the commencement in feebly acid solu- 
tions, and at a later period transferring them sometimes to 
fresh solutions, and at other times removing the alkaline reac- 
tion by frequent addition of a small quantity of acid. 

The tendency of solutions to become alkaline by means of the 
plants vegetating in them, and the injurious effect of an alka- 



EXPERIMENTS ON VEGETATION IN SOLUTIONS. 373 

line solution on the growth of plants, were observed by Knop 
and Stohmann. 

In the following are communicated the experiments of 
Knop and Stohmann on the vegetation of maize, in watery- 
solutions. 

I. — Experiments of Knop. 

Knop based his experiments with maize on the earlier obser- 
vations which he had made on the vegetation of barley and 
cresses (see *Chem. Central Blatt,' 1861, s. 564). According to 
these observations the graminese require for their growth nothing 
more than a normal solution, which contains sulphate of mag- 
nesia, nitrate of lime, and nitrate of potash, according to the 
proportion MgOS03 + 2CaONOg + 2KON05, in which phosphate 
of iron was suspended, and phosphate of potash as required was 
dissolved. The normal solution A made according to the above 
formula contained in sframmes — 





100 cent. cub. 


500 cent. cub. 


600 cent. cub. 


Nitric acid 


0-2160 


1-0800 


1-2960 


Sulphuric acid 


0-0495 


0-2475 


0-2970 


Lime 


0-0684 


0-3420 


0-4104 


Magnesia 


0-0233 


0-1165 


0-1398 


Potash . 


00940 


0-4700 


0-5640 



0-4512 2-2560 2-7072 

In consequence of using the solution in a more dilute form 
in the first period, in order to promote a better radication, 600 
cubic centimetres of the above solution were employed at this 
time ; at every other period, 500 cubic centimetres were measured 
off, and to this last quantity the phosphate of potash was now 
added in the proportion indicated. The mixture, therefore, had 
the following composition in the five periods. The potash 
which was added as KOPOg, and as KONOg, are given separately 
and united with a bracket. 

Period 
I. 12 cent. cub. solution of KOPO5,* 600 cent. cub. normal solution A 
IL 10 ^, „ 500 

in. & IV. 20 „ „ 500 „ ,j 

V, 30 „ ,, 500 



* 10 cent. cub. of the solution contained exactly 1 decigt-amhie of KOPOj. 



374 APPENDIX E. 

In these solutions are contained in grammes, — 



Nitric acid 


Per. I. 


Per. II. 


Per. III. & IV. 


Per. V. 


1-2960 


1-0800 


1-0800 


1-0800 


Sulphuric acid . 


0-2970 


0-2475 


0-2475 


0-2475 


Phosphoric acid 


0-0750 


0-0625 


0-1250 


0-1875 


Lime .... 


0-4104 


0-3420 


0-3420 


0-3420 


Magnesia .... 


0-1398 


0-1165 


0-1165 


0-1165 


Potash ... 1 


0-5640 


0-4700 


0-4700 


0-4700 


0-0490 


0-0408 


0-0816 


0-1224 


2-8312 


2-3593 


2-4626 


2-5659 



With the exception of the mixture used in Period V., there 
was added to the others also 0"1 gramme of phosphate of iron. 

The duration of these periods was accidental, depending on 
fluctuating meteorological conditions of the atmosphere, but 
was so far regulated that a distant period was marked whenever 
almost exactly 1 litre of water had been exhaled through the 
leaves of the plants. At this time the remainder of the liquid 
was drawn off for analysis, and the vessel filled with a fresh 
solution. 

In the following the results of the analysis are given along 
with the chief periods and circumstances of the experiments. 
In the analytical results in column A, is placed the total quantity 
of each acid, and salt received by the plant in that particular 
period ; in column b, the bases and acids found by analysis in 
the remainder of the fluid ; in column c, the difference between 
A and B, indicating the quantity of bases and acids absorbed by 
the plants. Further, the relations of the bases to each other, 
and that of magnesia to sulphuric acid (calculated from column 
a), are given; the quotients also express the proportions in 
which these matters were given to the plants at the begin- 
ning of the period. Immediately underneath, indicated by 
' absorbed,' are placed the same proportions, calculated from 
column c, in order to show in what ratio the plant has selected 
these matters (when there does exist a determinate power of 
selection). 



EXPEEIMENTS ON VEGETATION IN SOLUTIONS. 



375 



SUMMARY OF THE FOOD GIVEN TO A PLANT OF MAIZE AND ASSI- 
MILATED BY IT. 

I. Period. From May 12 to June 12. — At the commence- 
ment the plant weighed 8 grammes * ; and had six leaves with a 
surface of 264 square centimetres; water exhaled during the 
time = 1 litre. This period was divided into three sections, in 
which at first dilute solutions were used. The mixtures 
were in, — 





Section I. 




Section II. 


Section III. 


Solution of KOPO 5 


2 cent. 


cub. 


4 cent. cuh. 


6 cent. cub. 


Normal solution A . 


100 


jj 




200 


)) 


300 


Distilled water , 


198 


» 




96 


j> 


)» 


Total fluid 


300 


)) 




300 


j> 


306 


Phosphate of iron 


0-1 


gramme 


0-1 


gramme 


0-1 gramm 



There were added as the solution was absorbed by the plant, — 

I. Section = 80 cent. cub. distilled water 
II. „ = 350 
III. „ =570 „ 

1000 cent. cub. = l litre 

The residue from each section = 300 cent, cub., were united 
and analysed. 

Nitric acid . 
Sulphuric acid 
Phosphoric acid 
Lime . 
Magnesia 
Potash 



A 


B 


C 


1-2960 


? 


? 


0-2970 


0-1240 


0-1730 


0-0750 


0-0000 


0-0750 


0-4104 


0-1480 


0-2624 


0-1398 


0-0640 


0-0758 


0-6131 


0-2280 


0-3851 



2-8313 



0-5640 



0-9713 



In the first of the following lines are placed the proportions 
of the matters given to the plants, calculated from column A ; 
in the second, the calculations are made from column c : — 



Given ; 



CaO 



= 2-9 



Absorbed: -5^=3-4 



CaO ' MgO 

J52 = 1.5; ^2^=2-2 
CaO MgO 



* The maize seed were made to germinate in the month of April in well washed 
sand; the young plants weighed on the 12th May, 8 grammes; on drying the residue 
weighed scarcely more than the seeds. 



376 



APPENDIX E. 



II. Period. From June 12 to July 20. — At the commence- 
ment the plant weighed 65 grammes, and had nine leaves with 
a surface of 648 square centimetres ; water exhaled = 1 litre ; the 
plant received 0*1 gramme of phosphate of iron suspended in 
the water about the roots, the roots became of a reddish yellow 
colour. 



Nitric acid . 
Sulphuric acid 
Phosphoric acid 
Lime 
Magnesia 
Potash . 



A 


B 


C 


1-0800 


? 


? 


0-2475 


01704 


0-0771 


0-0625 


0-0000 


0-0625 


0-3420 


0-1912 


0-1508 


0-1165 


0-0860 


0-0305 


0-5110 


0-3120 


01990 



2-3595 



Proportions of bases and acids, — • 
CaO 



0-7596 



SO, 



0-5199 



Given: ±^f±i = 2-9 ; ^ = 1-5 , 

MgO ' CaO ' MgO 



:2-l 



Absorbed: -5^=5-0; ^ = 1-3; -^=2-5 
MgO ' CaO ' MgO 

III. Period. From July 20 to 27. — At the commencement 
the plant weighed 73 grammes, and had eleven leaves with a 
surface of 720 square centimetres ; water exhaled = 1 litre ; 
to the solution was added 0*1 gramme of phosphate of iron; 
radication strong. This period differs from the preceding in the 
quantity of KOPOg given being double. 



Nitric acid . 
Sulphuric acid 
Phosphoric acid 
Lime 
Magnesia 
Potash . 



A 


B 





1-0800 


? 


? 


0-2475 


0-1716 


0-0759 


0-1250 


0-0000 


0-1250 


0-3420 


0-1440 


0-1980 


0-1165 


0-0860 


0-0305 


0-5518 


0-2160 


0-3358 



2-4628 



Proportions of bases and acids, — 
Griven : 



0-6176 



CaO_., Q K0_, . 
M^-^'^'C^-^"^ 



0-7652 



= 2-1 



Absorbed : 



CaO. 
MsO' 



r 1 KO , ^ 



SO3 
MgU 

^2^ = 2-4 
Mo-0 



EXPEKIMENTS ON VEGETATION IN SOLUTIONS. 377 

IV. Period. From July 27 to August 1. — At the commence- 
ment the plant weighed 147 grammes, had eleven leaves, with a 
surface of 1160 square centimetres; water exhaled = 1 litre; 
to the solution was added 0*1 gramme of phosphate of iron ; the 
roots became distinctly reddish yellow. The plants received 
twice as much KOPO5 ^^ ^^ ^^® second period. 



Nitric acid . 
Sulphnric acid 
Phosphoric acid 
Lime 
Magnesia 
Potash . 



ABC 

1-0800 ? ? 

0-2475 0-1374 0-1101 

0-1250 0-0000 0-1250 

0-3420 0-1188 0-2232 

0-1165 0-0719 0-0446 

0-5518 0-1296 0-4222 



2-4628 0-4617 0-9211 



Proportions between bases and acids, — 

^ . CaO o f. KO , n SO, f, 1 

MgO CaO MgO 

Absorbed: ^ = 5-0; J^=l-8;-^ = 2-3 

MgO CaO MgO 

To ascertain how far the results from this artificial mode of 
cultivation maybe compared with those produced under natural 
circumstances, maize of the same kind was planted in the 
garden in the middle of May. The latter were exposed to the 
same atmospheric conditions as the experimental plants. On 
August 1, a plant from the garden of the same period of 
vegetation as the experimental plant, with also fifteen leaves, 
and visible male flowers, weighed 1260 grammes, that is to say, 
seven times as much as the artificially reared plant. The stem 
of the garden plant from the lower knot to the summit of the 
flower-stalk measured 150 centimetres, being three times the 
height of the experimental plant. 

V. Period. From August 1 to 10. — At the commencement 
the plant weighed 173 grammes; the stem was 52 centimetres 
high ; in the middle of the period the plant had fifteen large 
fine green leaves, with a surface of 1420 square centimetres. 
In this period double the quantity of water (2 litres) was 
exhaled, and as the older roots were distinctly reddish yellow in 
colour, the plant received no more phosphate of iron, but thrice 
as much phosphate of potash as in the second period. On 



A 


B 


c 


1-0800 


? 


? 


0-2475 


0-1640 


0-0835 


0-1875 


0-0020 


0-1855 


0-3420 


0-1236 


0-2184 


0-1165 


0-0790 


0-0370 


0-5927 


0-1894 


0-4033 



378 APPENDIX E. 

August 6 and 1, the male flower, consisting of seven single ears, 
was fully expanded from tlie sheath, the stem was strong, and 
70 centimetres high. On August 7, a fully formed female 
flower appeared ; on August 9, the anthers began to shed their 
pollen. 

Nitric acid . 
Sulphuric acid 
Phosphoric acid 
Lime 
Magnesia 
Potash . 

2-5662 0-5580 0-9277 

Proportions between bases and acids, — 

AWted:CJ = 5-9;^=l-8;||j=2.3 

As the plant in this period flowered, and earlier experiments 
had shown that maize dug up at the period of flowering and 
placed in river water furnished still ripe seeds, and also by the 
addition of the salts which the plant in each period had taken 
up in proportion to its increase in weight in the first four 
periods, it appeared that it must contain fully as much salts as 
the plant in its normal condition in the field takes up, if placed 
from this period only in distilled water. 

VI, Period. From August 10 to 16. — At the commencement 
the plant weighed 255 grammes, and had 15 fully expanded 
leaves with a surface of 2640 square centimetres : 2 litres of 
water were exhaled. 

On August 10, the anthers had almost completely shed their 
pollen. The stem shot up rapidly, and on the 12th it measured 
to the tip of the flower 1 metre in height. On the 13th a 
second female flower appeared, which was surrounded with 
paper to protect it from dust. On August 16 the height of the 
plant was I'l metre; it did not grow any more. The fruit- 
bearing stalk was, on August 16, already 2 decimetres long, and 
had below a thickness of 4 centimetres. 

On August 16, the water was drawn off and analysed. 



EXPERIMENTS ON VEGETATION IN SOLUTIONS. 379 

Present Not Present 

0-016 gramme potash Sulphuric acid (only indistinct opales- 

0-008 „ lime cence -with chloride of barium). 

O'OOl „ phosphoric acid Magnesia. 

Iron and silicic acid. 

From the circumstance that in this solution there was no 
silicic acid, it is plain that the glass vessel had furnished none 
to the fluid by decomposition in the course of one to two weeks. 

VII. Period. From August 16 to September 4,— 



16 


Angus 


t . 


. 


. 280 


grammes 


22 


>> 


at 9 


clock 


a.m. 316 






22 


)> 


„ 9 


>> 


p.m. 320 






28 


„ 


„ 9 


,j 


„ 330 






1 


Sept. 


„ 9 


,, 


„ 327 






4 


)> 


,, 9 


„ 


„ 317 







From September 1 the weight diminished by the drying of 
the leaves, and as this decrease was accidental, the plant was 
not thenceforward weighed. The leaves shrivelled. The plant 
had exhaled 3|- litres of water in the period. At this time it 
was placed in a vessel containing 1 '5 litres of water, to deter- 
mine what salts returned to the water by endosmone. The 
water was kept up at the same level by daily additions, and at 
last was 'allowed to exhale until the residue was 1 litre. In this 
litre were found 0-031 carbonate of lime and 0*007 carbonate of 
magnesia. Both salts were left in the basin undissolved after 
evaporation, and after the residue had been treated with water. 

In the water with which the residue left on evaporation in 
the basin had been extracted, the following substances were 
found in solution : — 

0-020 lime {"together with organic matter which 

0-0006 phosphoric acid -j reduced a solution of oxide of copper 
0-0034 potash Land potash. 

In this last solution not a trace of iron, sulphuric acid, or 
magnesia, was found. As the preceding analyses indicate, the 
solution of nutritive matters for graminese must have the 
following composition : — 

MgOSOg + 4CaON05 + 4KONO5 + xKOPO^ 
(Compare ^Chem. Central Blatt, 1861,' s. 465, 564, and 945.) 

* At all periods the plants threw off organic substances, but chiefly in the last 
periods. 



380 APPENDIX E. 

II. — Experiments of Stohmann. 

The experiments of Stohmann agree in their main results 
with those of Knop. According to these experiments, the 
maize plant grows to full maturity if in the beginning of May 
the seed which has germinated in water, and has shot forth 
roots, is placed in a solution containing the food of maize in the 
proportions in which they exist in the ashes, if at the same time 
there has been added to it so much nitrate of ammonia that to 
every part of phosphoric acid in the solution there are two 
parts of nitrogen, and if finally it has been diluted with dis- 
tilled water to a concentration of three parts of solid matter per 
1000 parts. The plants must grow in a sunny spot, and the water 
exhaled by the leaves must be daily replaced by distilled water, 
and the solution tested as to its reaction. The solution must 
always react, slightly acid, and be maintained in this condition 
by the addition from time to time of a few drops of phosphoric 
acid. If these conditions are fulfilled, there is no necessity for 
any artificial source of carbonic acid, but by means of the 
atmospheric carbonic acid alone there are produced fully formed 
plants which, under favourable circumstances, attain a height 
of 7 feet.* 

The experiments of Stohmann were more especially directed to 
the influence exercised on the growth of the maize plant by the 
withdrawal of one element of food. In this point the results differ 
from those of Knop. Whilst in the experiments of the latter 
maize was found to grow perfectly without silicic acid, soda, or 
ammonia, Stohmann made use of silicic acid in all his ex- 
periments, and found further that by the complete withdrawal 
of ammonia and even soda the plants grew quite well. 

On withdrawing ammonia completely and replacing it by 
nitric acid, Stohmann found that the plants grew perfectly well 
for the first ten to twelve days, then they became of a pale 
yellowish green, and the vegetation proceeded extremely slowly. 

If after a month's vegetation a little ammonia (in the form 
of nitrate or acetate) was given to the plants, they died very 
quickly. Without this supply of ammonia the blanched, sickly 
vegetation continued ; the plant did not die, and yet it could 

* According to Knop maize plants growing in a watery solution give off carbonic 
acid continuously from their roots. 



EXPEEIMENTS ON VEGETATION IN SOLUTIONS. 381 

not be said to live.* In the experiments made without socla^ it 
was found that the plant could dispense with this substance at 
first, but its progress was soon arrested if the soda was com- 
pletely withdrawn. The nitrate of lime of the normal solution 
was in another experiment replaced by a corresponding quan- 
tity of nitrate of magnesia. The growth of the maize plant 
was after a short time much retarded, only a few small, thin 
leaves being developed. By the addition of a little nitrate of 
lime to the growing plant, the most remarkable change was, 
however, produced. Scarcely five hours elapsed before the 
growth of the plant, which had been stationary for four weeks, 
awakened to a new life, and proceeded from this time forth in 
the best manner possible. A plant without the after addition 
of nitrate of lime remained stationary, making no progress 
whatever : the maize plant, therefore, requires lime immediately 
after the commencement of its growth. 

In an experiment in which the magnesia was replaced by 
nitrate of lime, the same result was obtained as when lime was 
wanting. In this case, also, the vegetation was very poor. A 
supply of magnesia, in the form of nitrate, exerted here also 
the most favourable action, only the effect was not so quickly 
produced as in the case of lime. 

Even by the complete withdrawal of nitric acid the maize- 
plant did not grow. In these experiments it is true the alkalies, 
as well as the alkaline earths, were in part supplied in the form 
of sulphates and chlorides. Chlorine and sulphuric acid, how- 
ever, are required only to a limited extent in the vegetable 
organism. The same holds good in the experiment without 
nitrogen. According to these experiments, therefore, a plant 
is not developed if one of its elements of food is wanting, and 
the complete replacement of one element of food by another 
one similar to it, is hence completely out of the question. The 
result may, however, be different with the reciprocal 'partial 
replacement of similar elements of food ; and Stohmann is about 
to take up this question. 

The form in which the food was supplied was the following, f 

* Compare Knop, ' Chem. Central Bl. 1862,' s. 257. 

t To form a complete solution of all matters, and to remove the alkaline re- 
action, the fluid was first properly diluted with water and so much weak hydro- 
chloric and later phosphoric acid was added as to make the reaction distinctly 
feehly acid. 



382 



APPENDIX E. 



The silicic acid was always supplied in the form of silicate of 
potash; the potash as nitrate. In the series of experiments 
(3) which were made without nitric acid, sulphate of potash 
was used instead of the nitrate. 

The phosphoric acid was used in the form of 2NaO, HO, POg f 
24HO ; in experioaental series 5, in which soda was excluded, a 
potash salt was used, 2K0, HO, PO5, of which a concentrated 
solution was prepared, containing a known quantity of potash and 
phosphoric acid. As the phosphate of soda contained more 
soda than was requisite in the composition of the ash, there 
was thus in the fluids in the experimental series 1 to 7 an excess 
of this base ; at a later period, a correspondingly smaller 
quantity of phosphate of soda and more of the potash salts 
were employed. 

The sulphuric acid was in the form of sulphate of magnesia, 
with the exception of 7, in which sulphate of ammonia was used, 
the magnesia required was added in the form ^ of nitrate of 
magnesia. 

The oxide of iron was supplied in the form of pure sublimed- 
chloride ; the lime as nitrate, and in the case of 3 as chloride of 
calcium ; the ammonia as nitrate, sulphate, or chloride. 

It was scarcely possible to avoid using a larger or smaller 
excess of one or other of the substances. This was particularly 
the case with soda and chlorine. These deviations will be best 
shown in the following tables. 

JE:rperimental series. 



Potash 
'Soda . 
Lime . 

Magnesia . 
Oxide of iron 
Sulpliimc acid 
Chlorine 
Phosphoric acid 
Silicic acid . 
Nitrogen 





1 


2 


3 


4 


5 


6 


7 




■a 


^ 


^ 


bo 


1 


1 

-4J 


<l> 


^1 


1 









5 




^ 


i 3 













^ 


k 




35-9 


3o-9 


52-0 


35-9 


35-9 


35-9 


35-9 


35^-9 


1-0 


8-0 


8-0 


8-0 


8-0 


— 


1-0 


1-0 


10-8 


10-8 


10-8 


10-8 


10-8 


10-8 


— 


19-2 


6-0 


6-0 


6-0 


6-0 


6-0 


6-0 


137 


— 


2-3 


2-3 


2-3 


2-3 


2 3 


2-3 


2-3 


2-3 


5-2 


0-2 


5-2 


26-9 


26-9 


5-2 


5-2 


5-2 


1-3 


19-7 


3-1 


66-5 


16-8 


3-1 


3-1 


3-1 


91 


9-1 


9-1 


9-1 


9-1 


91 


9-1 


91 


28-5 


28-5 


28-5 


28-5 


28-5 


28-0 


28-5 


28-5 


18-2 


18-2 


18-2 


— 


18-2 


18-2 


18-2 


18-2 



EXPERIMENTS ON VEGETATION IN SOLUTIONS. 



383 



Summary of the weights of the crops. 



is 


1 


Parts of plants 


1 
1 

P 


o 


'4H 
O 

r 


1 

a 

S 
bo 

O 


Proportion of 

the weight 

of the seed to 

that of the crop 

after deduction 

of the ash 


From 


Eoots . 


grms. 
10-36-| 


grms. 


per cent. 


grms. 






the 
garden 


Stem . 
Leaves . 

„ of the head 


52-39 1 

42-39 

28-51 


15-24 


11-4 


— 








Grains . 


190-14 


3-42 


1-8 












3 heads 


22-66 


0-54 


2-4 





— 


1. 


A 


Entire plant . 
Roots . 


346-45 
3-92^ 


19-20 


5-5 


327-25 


1:3147 






Stem . 
Leaves . 


9-67 
11-79 ' 


3-97 


13-1 


— 


— ■ 






,, of heads . 


4-91 














Head with grain . 


34-09 


0-82 


2-4 





— 






Entire plant , 


64-38 


4-79 


7-5 


59-59 


1:573 




B 


Straw . 


27-36 


4-35 


15-9 





— 






Heads . 


4-24 


0-14 


3-4 





— 






Grains . 


24-57 


0-56 


2-3 





— 






Entire pla.nt . 


56-17 


5-05 


8-9 


51-12 


1:491 




C 


,, ,, . . 


55-52 


5-94 


10-7 


49-58 


1:477 


2. 


D 


)) )) • 


62-44 


6-49 


10-4 


55-95 


1:538 




A— C 


,, ), • 


1-19 


— - 


— 





— 




D 


!) )I • 


2-39 


0-54 


22-8 


1-85 


1:18 


3. 


A— B 


)) !> • 


0-204 


— . 


— . 








4. 


A 


Roots . 


0-45 


0-10 


22-8 


__ 


— 






Stem and leaves . 


1-03 


0-17 


16-7 





— 






Entii-e plant . 


1-48 


0-27 


18-2 


1-21 


1: 12 




C 


jj J) * 


10-90 


0-92 


8-5 


9-98 


1 : 96 




D 


?J S) • 


39-48 


5-57 


14-1 


33-91 


1 : 326 


5. 


A 




49-63 


5-21 


10-5 


44-42 


1 :427 




B 


!> >) • 


32-31 


3-36 


10-4 


28-95 


1: 278 


6. 


A 


J) )) • • 


0-30 


— 


— . 





— 




B 


IJ I) • 


84-30 


8-22 


9-75 


76-08 


1:731 


7. 


A 


!> J) • 


0-82 


0-18 


21-4 


0-64 


1:6 




B. C 


" • ■ 


6-01 


0-82 


13-7 


5-19 


1:50 



EEMARKS ON THE SUMMARY OF THE WEIGHTS OF THE CROPS. 



I. Plants A, B, c, and d grew in normal solutions. Plants A 
and B were placed in the solution on July 1, and plant A was 
gathered on September 10, fully ripened ; its total height was 
202 centimetres. The plant from the garden soil with which it 
was compared was of middle size. Plant b gathered on Sep- 
tember 27, was fully grown, and had a height of 127 centimetres. 
Plants c and d were placed in the normal solution on June 10, 



384 APPENDIX E. 

they did not attain their full growth ; both were gathered on 
October 28. 

II. Commencement of experiment in solutions without avi- 
TYionia on June 10. — a and b received on July 12 a supply of 
0*2 gramme nitrate of ammonia ; on July 23 they were placed 
in a fresh solution, to which was added 0-2 gramme acetate of 
ammonia ; both plants died on July 31. Plants c and d received 
normal solution on August 4, which was neutralised with phos- 
phoric acid ; c died on August 9, d recovered somewhat, but 
remained sickly till gathered on September 27. 

III. Experiments without nitric acid. — Commencement on 
June 10; rapid decay of the plants; by July 1 A and b were 
already dead. 

IV. Experiments ^vithout nitrogen. — Commencement on 
June 10. In the first week the growth was excellent, but in the 
second week it came to a stand, a lived till gathered on Sep- 
tember 27 ; height 15 centimetres, length of roots 82 centi- 
metres. Plants c and d received on July 11 each 0*2 gramme 
nitrate of ammonia, and on July 17, also, the same quantity. 
The influence of this salt was rapidly visible. On August 4, c 
and D received normal solution. Plant c was gathered on Septem- 
ber 27, height 75 centimetres. Plant n gathered on November 
15, was in a healthy state, and had attained a height of 120 
centimetres. 

V. Experiments without soda. — Commencement June 10. 
The early vegetation was very luxuriant ; in the end of July, 
however, the plants weVe not progressing. On August 4, the 
plants received normal solution ; two died, but a and b made 
further progress. A and b were gathered on October 30, height 
of A, 205 centimetres ; b stunted. 

VI. Experiments without Hone. — Commencement June 10. 
Plant A had reached a height of 2 centimetres on July 17 ; but 
made no further progress, b received on July 1, O'l gramme 
lime in the form of nitrate, and, on August 4, normal solution, 
vigorous growth. It had on November 15 four stems respec- 
tively 107, 95, 75, 70 centimetres high, which were covered 
with leaves, and had eight well-developed heads of fruit. 



EXPEEIMEJSTTS ON THE GEOWTH OF BEANS. 



385 



YII. Experiments without magnesia. — Commencement June 
10. Progress as in Experiment VI., and gathered as it was 
making no visible progress. B and c received on July 17, O'l 
gramme magnesia, and on August 4 normal solution, gathered 
September 27 ; height of b, 23 centimetres ; of c, 42 centimetres. 
Both had male flowers without pollen, and no female flowers. 

On comparing his experimental plants with those which grew 
in the ground, both in respect to weight of the crop and to 
amount of ash and its composition, Stohmann concluded that 
we may indeed convert a plant of maize into a ivater-'plant, but 
that maize cannot grow in a normal condition in solutions of its 
food. Further, his experiments showed in a positive manner 
that the soil played a determinate part in the nutriment of 
plants — absorption of alkalies — and that plants in the absorp- 
tion of their food must themselves take an active part (compare 
Henneberg's 'Journal fiir landwirthschaft, 1862,' s. 1, and 'An. 
der Chem. und Pharm.,' bd. cxxi. s. 285). 



APPENDIX F (page 109). 

EXPERIMENTS ON THE GROWTH OF BEANS IN POWDERED TURF. 

To complete the experiments on vegetation described at 
page 106, the results of the entire crops are now given in the 
following table : — 

Dry suhstance of the hean plants in grammes. 



Seed 

SheU 

Leaves .... 

Stem 

Eoots ..... 

Total weight 


I. Pot 

fully 

saturated 


II. Pot 

half 

saturated 


III. Pot 

quarter 

saturated 


IV. Pot 
pure 
turf 


93-240 
25-948 
19-420 
26-007 
58-399 


66-127 
18-393 
15-797 
20-107 
36-368 


50-463 
13-658 
12-477 
15-710 
25-411 


7-069 
2-631 
1-979 
5-676 
3-063 


223-014 


156-792 


117-719 


20-418 



These numbers completely confirm the conclusions drawn 
from the weight of the seeds alone. If the crop from the pure 

C C 



386 APPENDIX G. 

turf be taken as unity, the weights of the entire crops bear the 
following proportions — 

1 : 5-7 : 1'1 : 10-9 

or if the weight of the crop in the | saturated turf be called 2, 
and that of the i and fully saturated turf be compared with it, 
the following proportions are found — 

2:2-7: 3-8 

If the weight of the crop furnished by the pure turf be sub- 
tracted from each of the others, and the weight of the crop in 
the ^ saturated turf be taken at 2, then the crops in the -^ and 
fully saturated turfs bear the following proportions to it — 

2:2-8: 4-2 



APPENDIX a (page 238). 

Extract from the Report to the Minister of Agriculture at 
Berlin, on Japanese Husbandry ; hy Dk. H. Maeon, Mem- 
ber of the Prussian East Asiatic Expedition. 

SECTION I. 

SOIL AND MANURING. 

The Japanese empire stretches from the 30th to the 45th 
degree of north latitude. The average temperature and distribu- 
tion of heat constitute a climate embracing all the gradations 
between those of central Grermany and of Upper Italy. A soli- 
tary tropical palm, not fully developed, grows by the side of the 
northern pine, rice and cotton along with buckwheat and barley. 
Everywhere on the chains of hills, which cover the whole 
country like an irregular fine network, the pine predominates, 
stamping upon the landscape that homely northern character, 
which affords so cheering a sight to the northern traveller, who 
reaches these shores after having passed through the hot and 
luxuriant regions of the tropics. In the valleys, on the other 
hand, the burning south holds sway, covering the ground with 
a rich vegetation of rice, cotton, yams, and sweet potatoes. 



JAPANESE HUSBANDEY. 387 

Hundreds of footpaths and small ravines lead to charming 
transitions between pine and cotton, hill and dale ; everywhere 
there is a gay medley of laurels, myrtles, cypresses, and above 
all, shining camellias. 

The land is of volcanic origin, and the entire surface belongs 
to the tufa and the diluvium formation. The soil on the hills 
consists of an extremely fine, yet not over fat brown clay ; 
whereas that of the valleys is throughout the country, with 
some trifling modifications, of a black, loose, and deep garden 
mould, which upon trial in different places I found extended to 
a depth of 12 to 15 feet, being throughout of the same quality, 
though somewhat more compact in the deeper layers. An 
impermeable stratum of clay probably underlies this arable 
crust. As the clay strata of the mountains, in consequence of 
the frequent and copious falls of rain, give rise to a multitude 
of springs, which are everywhere at hand, and may thus easily 
and without any great skill, be turned to account for the purpose 
of irrigation ; so the impermeability of the stratum underlying 
the surface soil in the valleys enables the Japanese husbandmen 
to turn the soil at pleasure into a swamp, for the cultivation of 
rice. 

Whichever way one may feel inclined to decide the question^ 
whether the present fruitfulness of the soil is simply the arti- 
ficial product of cultivation continued for a period of several 
thousand years, or whether this fertility existed from the begin- 
ning, making this people love and cherish the labours of agricul- 
ture, this much must be granted, at all events, that the clay 
of the diluvium, the mild climate, and abundance of water, 
afforded all the conditions, and the most convenient means, for 
a thriving cultivation. All these advantages have been most 
carefully turned to account by an industrious, ingenious, and 
sober people; and husbandry in Japan has become a truly 
national occupation. The Japanese have thoroughly mastered 
the difficult task of maintaining agriculture in a state of the 
highest perfection, although its pursuit is entirely in the 
hands of peasants and yeomen, who take rank in the sixth and 
last but one class of the social scale, and no Japanese gentleman 
is a farmer. There are no agricultural institutions for instruc- 
tion in husbandry, no agricultural societies, no academies, no 

c c 2 



388 APPENDIX G. 

periodical press to spread the teachings of science. The son 
simply learns from the father ; and as the father knows quite as 
much as his grandfather and great grandfather before him, so 
he pursues exactly the same system of husbandry as any other 
peasant in any other part of the empire; it is a matter of 
perfect indifference where the young agriculturist learns his 
business. The young pupil in husbandry will always be able to 
master a certain small amount of information which the expe- 
rience of ages has shown to be true, so that it may be looked 
upon as positive knowledge, and a sort of hereditary heirloom. 

I must confess that I experienced a feeling of deep humilia- 
tion on many occasions, when with this simple knowledge, and 
the safe and uncontested 'practical ccpplication of it in hus- 
bandry before my eyes, I thought of home. We boast that we 
are a civilised nation ; in our land men of the highest intellectual 
attainments devote their best energy to the improvement of 
agriculture ; we have everywhere agricultural institutions and 
agricultural societies, chemical laboratories and model farms, to 
increase and diffuse the knowledge of husbandry. And yet how 
strange that, despite all this, we still go on disputing, often so 
vehemently and acrimoniously, about the first and most simple 
scientific principles of agriculture ; and that those who earnestly 
search after truth are forced to admit the infinite smallness of 
their positive and undisputed knowledge ! How strange also 
that even this trifling amount of positive knowledge has as yet 
found so little application in practice ! 

Among the great questions which still remain in dispute with 
us, whilst in Japan they have long since been settled in the 
laboratory of an experience extending over thousands of years, 
I must mention as the most important of all, that of manuring. 
The educated sensible farmer of the old world, who has in- 
sensibly come to look upon England, with its meadows, its enor- 
mous fodder production and immense herds of cattle, and in 
spite of these with its great consumption of guano, ground 
bones, and rape-cake, as the beau ideal and the only possible 
type of a truly rational system of husbandry, would certainly 
think it a most surprising circumstance to see a country even 
much better cultivated, without meadows, without fodder pro- 
duction, and even without a single head of cattle, either for 



JAPAJ!^ESE HUSBANDRY. 389 

draught or for fattening, and without the least supply of guano, 
ground bones, saltpetre, or rape-cake. This is Japan. 

I cannot help smiling when I remember how, on my passing 
through England, one of the great leaders of agriculture in that 
country, pointing to his abundant stock of cattle, endeavoured 
with an authoritative air to impress upon my mind the following 
axioms, as the great secret of true wisdom : — ' The more 
fodder, the more flesh ; the more flesh, the more manure ; the 
more manure, the more grain ! ' The Japanese peasant knows 
nothing of this chain of conclusions ; he simply holds fast to one 
indisputable axiom, viz. without continuous manuring there can 
be no continuous production. A small portion of what I take 
from the soil is replaced by nature (the atmosphere and the 
rain), the remainder I must restore to the ground ; the manner 
in which this is done is a matter of indifference. That the 
produce of the land has first to pass through the human body 
before it can be returned to the soil, is, as far as manuring is 
concejned, simply a necessary evil, which always involves a 
certain loss. As to the intermediate stage of cattle feeding, 
which we deem so requisite in our system, the Japanese farmer 
cannot at all see its necessity. He argues in his way that it 
must cost a great deal of unnecessary and expensive labour to 
have the produce of the field first eaten by cattle, so troublesome 
and expensive to breed, and that this system must involve more 
considerable loss of matter than his own. How much more 
simj)le it must be to eat the corn yourself, and to produce your 
own manure ! Far from me be it, however, upon the ground of 
the so widely differing results to which the developement of 
agriculture has led in the two lands, to pass judgement upon our 
system of husbandry, and to exalt unduly that of the Japanese 
by attributing superior intelligence to that nation. Circum- 
stances have brought about the results in question, and the fol- 
lowing more especially have exercised a decided influence in the 
matter. The religious belief of the two great sects in Japan, 
the Sintoists and the Buddhists, forbids the eating of flesh, and 
not alone of flesh, but of everything derived from animals 
(mik, butter, cheese) ; this prohibition, of course, disposes of one 
of the principal objects for which cattle are bred. Even sheep, 
if kept for the wool alone, would not pay, as our farmers begin 
to find out even in Grermany. 



390 APPENDIX G. 

The very limited area of the homesteads in Japan also makes 
the maintaining of cattle superfluous. The smallness of the 
farms must not be attributed, however, to any excessive tendency 
to subdivision of landed property, but to the fact that the land 
belongs to the great princes or Daimios of the country, who have 
bestowed it in fee upon the lower nobility. The latter, again, 
being precluded by the institutions of the country from farming 
their own estates, have parcelled the land out, apparently from 
time immemorial, on perpetual leases, among the peasantry of 
the country. The size of these farms varies from two to five 
acres ; the limitation having been most likely determined either 
by their natural position, or from the course of some brook or 
rivulet. Now, as this limited area is intersected moreover by 
drains and ditches, it will be readily seen that there is hardly a 
plot of ground to be found where the use of beasts of burden 
might be profitably had recourse to. 

Now, with us matters are very different in these respects. 
We have a notion that we could not possibly exist in health and 
vigour without a considerable consumption of meat, although 
we have the fact constantly before our eyes, that our labourers, 
who assuredly require as much strength as any other class of 
society, are, for the most part, involuntary Buddhists. Our 
farms are always sufficiently large to preclude the notion of 
working them by hand, even leaving out of consideration the 
important circumstance that the price of labour is rather too 
high, in proportion to the value of the produce, to admit of 
such a system of farming. But that the culture of the soil is 
ever3rwhere in the world in direct ratio to the division of the 
land is a well-established fact, of which the reality and signifi- 
cance are made most clearly apparent to the traveller who 
passes from the north of Grermany to Japan, via England. 

The only manure-producer, therefore, in Japan is man ; and 
we need not wonder that the greatest care should be bestowed 
in that country upon the gathering, preparing, and applying his 
excrements. Now, as their entire course of proceeding contains 
much that is highly instructive for us, I consider it my duty to 
give as detailed a description of it as possible, even at the risk 
of offending the delicate feelings of the reader. 

The Japanese does not construct his privy as we do in 



JAPAIN'ESE HUSBANDRY. 391 

Grermany, in some remote corner of the yard, with half-open 
rear, giving free admission to wind and rain ; but he makes it 
an essential part of the interior of his dwelling. As he ignores 
altogether the notion of a ' seat,' the cabinet, which, as a general 
rule, is very clean, neat, and, in many cases, nicely papered or 
painted and varnished, has a simple hole of the shape of an 
oblong square running across and opposite to the entrance door, 
and serving to convey the excrements into the lower space. 
Squatting over this hole, with his legs astride, the Japanese 
satisfies the call of nature with the greatest cleanliness. I 
never saw a dirty cabinet in Japan, even in the dwelling of the 
very poorest peasant. It appears to me that there is something- 
very practical in this form of construction of a closet. We, in 
Germany, construct privies over our dung-holes, and behind our 
barns, for the use of our farm-servants and labourers, and pro- 
vide them with seats with round holes. With even only one 
aperture, it is too often found that after a few days' use they 
look more like pigstyes than closets for the use of man, and this 
simply because our labourers have a decided, perhaps natural, 
predilection for squatting. The construction of the Japanese 
privies shows how easy it would be to satisfy this predilection. 
To receive the excrements, there is placed below the square 
hole a bucket or tub, of a size corresponding to it, with pro- 
jecting ears, through which a pole can be passed to carry the 
vessel. In many instances a large earthen pot, with handles, is 
used, for the manufacture of which the Japanese clay supplies 
an excellent material. In some rare instances in the towns, I 
found a layer of chopped straw or chaff at the bottom of the 
vessel, and occasionally also interspersed among the excrements, 
a proceeding which, if I mistake not, has of late been recom- 
mended also in Grermany. As soon as the vessel is full, it is 
taken out and emptied into one of the larger dung-vessels. 
These are placed either in the yard or in the field. They are 
large casks or enormous stoneware jars, in capacity of from 
8 to 12 cubic feet, let into the ground nearly to the brim. It 
is in these vessels that the manure is prepared for the field. 
The excrements are diluted with water, no other addition of 
any Jdnd being made to them, and stirred until the entire mass 
is worked into a most intimately intermixed fine paj). In rainy 



392 APPENDIX G. 

weather, the vessel is covered with a moveable roof to shield it 
from the rain ; in dry weather this is removed, to allow the 
action of the sun and wind. The solid ingredients of the pap 
gradually subside, and fermentation sets in ; the water evapo- 
rates. By this time the vessel in the privy is again ready for 
emptying. A fresh quantity of water is added, the whole mass 
is again stirred and most intimately mixed together, in short, 
treated exactly like the first emptying. The same process is 
repeated, until the cask or pan is full. After the last supply 
of excrements, and thorough mixing, the mass is left, according 
to the state of the weather, for two or three weeks longer, or 
until it is required for use ; but under no circumstance is the 
manure ever employed in the fresh state. This entire course 

OF PROCEEDING CLEARLY SHOWS THAT THE JAPANESE ARE NO PAR- 
TISANS OP THE NITROGEN THEORY, AND THAT THEY ONLY CARE FOR 

THE SOLID INGREDIENTS OF THE DUNG. They Uavc the am,monia 
exposed to decomposition by the action of the sun, and 
its volatilisation by the luind, but take the greater care 
to shield the solid ingredients from being wasted or swept 
away by rain, &c. As the peasant, however, pays his rent to 
his landlord not in cash, but in a certain stipulated percentage 
of the produce of his fields, he argues quite logically that the 
supply of manure from his privy must necessarily be insuflicient 
to prevent the gradual exhaustion of the soil of his farm; 
notwithstanding the marvellous richness of the latter, and in 
spite of the additional supply of manuring matter derived from 
the water of the brook or canal from which he takes his mate- 
rial for irrigation. He places, therefore, wherever his field is 
bordered by public roads, footpaths, &c., casks or pots buried in 
the ground nearly to the rim, urgently requesting the travelling 
public to make use of the same. To show how universally the 
economical value of manure is felt and appreciated in all classes 
of society in Japan, from the highest to the lowest, I need 
simply state the fact that, in all my wanderings through the 
country, even in the most remote valleys, and in the homesteads 
and cottages of the very poorest of the peasantry, I never 
could discover, even in the most secret and secluded corners, 
the least trace of human excrements. How very different with 
us, in Grermany, where it may be seen lying about in every 
direction, even close to privies ! 



JAPANESE HUSBAJN^DRY. 393 

I need not mention that the manure thus left by benevolent 
travellers is treated exactly in the same way as the family 
manure. 

But the excrements of the peasant contain also some other 
matter, which has not been derived from the soil of his fields, 
and which may be said to represent an additional importation 
of manure. The river, brooks, and canals, and the numerous 
little bays, abound in fish, which the religion of the Japanese 
permits him to eat, a permission of which he most largely 
avails himself. Fishes, crabs, lobsters, and snails are eaten in 
quantities, and these ultimately afford a most valuable item of 
contribution to the privy, and consequently to the fertilising 
field-manure. 

The Japanese farmer prepares also compost. As he keeps no 
cattle to turn his straw, &c. into manure, he is forced to incor- 
porate this part of his produce with the soil without ' animali- 
sation.' The method pursued to effect this object consists 
simply in the concentration of the materials. Chaff, chopped 
straw, horse-dung excrement gathered in the highways, tops 
and leaves of turnips, peelings of yams and sweet potatoes, and 
all the offal of the farm, are carefully mixed with a little 
mould, shovelled up in small pyramidal heaps, moistened, and 
covered with a straw thatch. I often saw also in this compost 
heaps of shells of mussels and snails, with which most of the 
rivulets and brooks abound, and which, in all parts close to the 
seashore, may be obtained in any quantities. The compost 
heaps are occasionally moistened and turned with the shovel, 
and thus the process of decomposition proceeds rapidly, under 
the powerful action of the sun. I have also often seen the 
shorter process of reduction by fire resorted to when there was 
plenty of straw, or where the manure was required for use 
before it could be got ready by the fermentation process. 

The half-charred mass was, in such cases, in so far as my own 
observation enabled me to judge, strewed directly on the seed 
sown in the ground. 

I think the treatment of this compost is another proof 
that the Japanese farmer does not care for the azotised matters, 
and that he strives to destroy all organic substances in his 
manure before making use of it. The great object of the 



394 APPENDIX G. 

Jaipanese farmer in all this is to turn his manure to account 
as promptly as possible. 

To attain this end, besides preparing his manures in the 
manner described, he has recourse also to the following means : — 

1. He applies his manures, and particularly his chief manure 
derived from his privy, invariably as much as possible in the 
liquid form. 

2. He knotvs no other mode of raanuring than that of top- 
dressing. 

When he wishes to sow, the land is laid in furrows, in the way 
to be more fully described hereafter, and the seed is strewn by 
hand, and covered with a thin and even layer of compost, over 
which liquefied and very dilute privy manure is poured. The 
manure is diluted in the buckets in which it is carried from the 
preparing tub or pots to the seed furrow, as this is the only 
way to ensure uniform intermixing of the materials. As this 
manure has fully fermented, it may without danger be brought 
into immediate contact with the seed, and thus materially assist 
the first radication. 

It may be that this Japanese system of manuring cannot as 
yet be introduced into Europe in its integrity. But with, such 
excellent results to show for their proceedings, we might surely 
take a few lessons from these old practical men, and employ them 
with such modifications as our social relations require. At all 
events we might adopt in principle the following : — 

1. The greatest possible concentration of manures, which 
must necessarily lead also to a material reduction of cost. 
When I stated that the Japanese does not trouble himself about 
the azotised matters in his manures, .and that his land is, not- 
withstanding, in a most flourishing state of culture, this is no 
proof, however, that it might not even he better^ perhaps, to en- 
deavour to fix the nitrogen too. If a more practical system can 
be devised, of which however I have my doubts, combining" the 
advantage of both, so much the better I But till something- 
better is discovered, we might surely adopt that which experi- 
ence has proved to be good. 

2. Top-dressing, which is of course necessarily connected with 
cultivation in drills or furrows. 

3. Liquid manuring ; not to the extravagant extent, however. 



JAPANESE HUSBANDRY. . 395 

in which it was sought to be carried out in England, but in ac- 
cordance with the present condition of German agriculture. 

4. Manuring with every crop. 

The Japanese never cultivates a crop without manuring it, 
but he gives each crop or seed exactly as much and no more 
manure than is required for its full developement. He does not 
care about enriching the soil for future crops. What he 
demands is simply a full crop in return for each sowing. How 
often do we hear our farmers talk about this manure being pre- 
ferable to that manure on account of its fertilising action being 
' more lasting ; ' yet with all our wise provision for the future, 
how far are we now behind the Japanese, who seem to look 
always to the next harvest only ! As they manure for each 
fresh crop, and the term ' fallow ' in our acceptation is en- 
tirely unknown to them, they are forced to distribute their 
yearly production of manure equally over the entire area of 
their land, which can be accomplished only by sowing in drills 
or furrows, and by top-dressing. 

The contrast between this rational system and the profuse 
application of our long straw manure over the whole surface of 
the field is truly glaring, 

I may also add here that the manure in the Japanese towns 
is never artifically turned into guano or poudrette, but is sent 
every night and morning in its natural form into the country 
around, to return again after a time in the shape of beans or 
turnips. Thousands of boats may be seen early each morning 
laden with high heaps of buckets full of the precious stuff, which 
they carry from the canals in the cities to the country. These 
boats come and go with the regularity of the post; it must be 
admitted, however, that it is a species of martyrdom to be the 
conductor of a mail boat of this kind. In the evening long 
strings of coolies are met with on the road, who having in 
the morning carried the produce of the country to the town, are 
returning home each with two buckets of manure, not in a solid 
and concentrated form, but fresh from the privies. Caravans of 
packhorses, which often have brought manufactured articles 
(silk, oil, lacquered goods, &c.), a distance of 200 to 300 miles 
from the interior to the capital, are sent home again freighted 
with baskets or buckets of manure ; in such cases, however, care 
is taken to select solid excrements. 



396 APPENDIX G. 

Thus in Japanese agriculture we have before us the represen- 
tation of a perfect circulation of the forces of nature ; no link 
in the chain is ever lost, one is always interlaced with the 
other. 

I cannot refrain here from drawing a parallel in this respect 
between the Japanese and our system. In our large farms we 
sell a portion of the productive power of our soil in the form of 
corn, turnips, or potatoes ; but our carts which convey the pro- 
ducts to the town or to the gates of the factory, bring back no 
compensation. One of the links of the chain is lost. There is 
another portion of our produce devoted to the feeding of large 
herds of cattle, of which a considerable amount is sent forth in 
the form of fat cattle, milk, butter, or wool ; this again is never 
returned, and thus a second link of the chain is lost. Another 
small portion we and our labourers consume. This last portion 
at least might be turned to proper account, if we only knew, 
like the Japanese, to save and use it more carefully and wisely. 
Will anyone venture to assert that the privy manure of our 
farms is of the least real importance ? I verily believe that under 
present circumstances, the privy manure of an estate of a thou- 
sand acres would be barely sufficient for half an acre of ground. 
There remains then, from our present agricultural system, out 
of the entire productive power withdrawn by the crops from the 
soil, only that portion returned by our cattle, a small part indeed 
of the whole, if we take into consideration its bulk, and reflect 
in how concentrated a form we have disposed of the rest of that 
power in the shape of grain, milk, or wool. 

It may be objected, I am quite aware, that it is strange that 
our system of keeping large stocks of cattle does succeed in 
leading to a high state of cultivation and abundant produce. I 
admit the fact, only let us ascertain first its true significance. 
It is, above all, necessary to settle about the true acceptation of 
the term ' culture.' If by ' culture ' is meant the capability of 
the soil to give permanently high produce, by way of real 
interest on the capital of the soil, I must altogether deny that 
our farms (with perhaps a few exceptions), can properly be said 
to be in a satisfactory state of culture. But we have by excel- 
lent tillage and a peculiar method of maniudng, put them in a 
condition to make the entire productive power of the soil avail- 



JAPANESE HUSBANDEY. 397 

able, and thus to give immediately full crops. It is not, how- 
ever, the interest that we obtain in such crops, but the capital 
itself of the soil upon which we are drawing. The more largely 
our system enables us to draw upon this capital, the sooner it 
will come to an end. The term * culture ' applied to such a 
proceeding is a. misnomer. The peculiar method of manuring 
alluded to consists merely in our endeavouring to feed the soil 
of our fields with the largest possible supply of azotised matter. 
Now, ammonia and the other azotised compounds may no doubt 
be looked upon as excellent agents to stir up the hidden and 
slumbering forces of the soil. But after all, these agents may 
be regarded somewhat in the light of a banker, who kindly ex- 
changes the pound we have to spend for thirteen shillings ; and 
then we can spend the change fast enough. This accounts for 
the large party amongst us who love and cherish the obliging 
banker. 

This is the great difference between European and Japanese 
culture. The former is simply a delusion, which will be detected 
sooner or later. Japanese cultivation, on the other hand, is 
actual and genuine ; the produce of the land represents indeed 
the interest of the capital of the soil's productive power. As 
the Japanese knows that he has to live upon that interest, his 
first care is devoted to keeping the capital intact. He only takes 
away from his soil with one hand, if he can make up the loss 
with the other ; and he never takes more than he can return. 
He never endeavours to force the production by large supplies 
of azotised matters. 

The fields in Japan do not, therefore, as a general rule, present 
that luxuriant aspect which gratifies our sight occasionally at 
home. There are no impenetrable forests of straw from six to 
eight feet high, to be seen, nor turnips weighing 100 lbs., with 
99 lbs. of water in them. There is nothing extravagant in the 
sight of Japanese crops. But what distinguishes them most 
favourably as corn/pared to ours is their certainty and uni- 
formity for thousands of years. The real ^produce of land 
can he calculated only by the average crops' of a long number 
of years. 

If additional proof were needed to show that the state of cul- 
tivation is very superior, and that the land yields abundant 



398 APPENDIX G. 

produce, I would point to the fact that the Japanese empire, 
which covers an area similar to Great Britain and Ireland, and 
of which one-half at the most, from the hilly nature of the 
country, can be looked upon as fit for tillage, not only contains 
a larger number of inhabitants than Grreat Britain and Ireland, 
but maintains them without any supply of food from other parts. 
Whilst Grreat Britain is compelled to import corn from other 
countries, to the extent of many millions per annum, Japan 
since the opening of its ports actually exports no inconsiderable 
quantities of food. 

SECTION II. 

TILLAGE OF THE SOIL. 

Deep cultivation of the soil has become a kind of proverb 
with our modern writers on agriculture ; and the principle of 
the system is, at least, fully admitted on all hands, the only 
objection occasionally raised against it being that it requires a 
large supply of manure. But the most enthusiastic admirer of 
the system in Europe can hardly conceive how universally and 
in what high perfection it is carried on in Japan. 

The Japanese husbandman has come to treat his field as a 
plastic material, to be turned to account in any way or form he 
pleases, just as a tailor may cut out of a piece of cloth cloaks, 
coats, trowsers, or vests, and occasionally makes the one out 
of the other. To-day we find a plot of ground covered with 
a wheat-crop ; in eight days the wheat is reaped, and one 
half of the field is transformed into a swamp thoroughly satu- 
rated with water, in which the farmer, sinking up to his knees, 
is busy planting rice, whilst the other half is a broad and dry 
plot, raised 2 or 2^ feet above the rice swamp, and ready to 
receive cotton, or sweet potatoes, or buckwheat. It often 
happens also that a square plot in the centre is turned into a 
dry bed, surrounded by a broad rice swamp ; and as the water 
must cover the surface of the latter only slightly, the levelling 
must have been effected with great care, and with the use of 
instruments. 

The whole of this work has been done by the farmer and his 
small family in a very short time. That it could be accom- 



JAPANESE HUSBANDRt. 399 

plished in so short a time is a proof of the great depth of the 
loose arable soil, even after a harvest; and that the farmer 
could venture to do so without troubling himself about the 
next crop, is a sign of the abounding tvealth of the soil in 
mineral constituents. It is only v^rhen great depth of the loose 
arable soil is combined with a plentiful store of mineral con- 
stituents that deep tillage of the ground can truly be resorted 
to. The description here given is not a mere fiction or creation 
of the imagination, but a faithful statement of facts such as I 
have had occasion to witness by the hundred. Considering that 
rice requires at least from 1 to 1^ feet of cultivated soil, and 
adding to this half the height of the raised bed, viz. 1 to 1^^ feet, 
this gives a cultivated depth of arable soil of from 2 to 3 feet. 

This system of working the land at pleasure either as a 
raised dry plot or as a swamp, is indeed, at present, in Japan, 
simply a proof of the existence of deep tillage ; but it is clearly 
evident that it must have been, at one time, also, the means of 
effecting it. If we are always to wait until we have collected a 
sufficient excess of manure (at the best but a very relative 
term), before proceeding to deepen the arable crust of our land, 
we may certainly predict that the system will but very rarely 
make any progress vv'ith us. Everybody knows that one cannot 
learn to swim without going into the water. 

The introduction and constant progress of the sj^stem of deep 
tillage has been powerfully assisted in Japan by the practice 
pursued from time immemorial of growing all crops in drills. 
With the advantage of this method we have also long been 
familiar. Among the favourable features presented by the 
cultivation of root crops, our books of agriculture always place 
in a prominent rank the fact that it enables the farmer to 
deepen the arable soil of his land. All our gardeners, at least, 
have long ago adopted it. 

I was not fully aware of the true importance of the method 
of growing crops in drills, until I had occasion to see it carried 
out to the fullest extent in Japan. We, in Europe, are as yet 
far from having adopted this plan as an essential part of our 
system of husbandry ; we look upon the question still in a very 
one-sided point of view, only in reference to the individual 
crop which we wish to groiu. But the Japanese farmer has 



400 APPENDIX Q. 

raised it to the rank of a system, by which he has fully eman- 
cipated himself from the necessity of paying, as we are com- 
pelled to do, the least regard to the rotation of crops. By its 
means he has truly become master of his land. He has not 
only succeeded in growing crops at the same time which used 
to follow each other, but he has carried to the highest perfec- 
tion the principle of mixed cultivation, which begins now to 
find favour also with our European farmers : he has, in this 
respect, put an end to our confused and hap-hazard way of 
mixing crops on the same field, having by the adoption of the 
method of drill planting, brought order and regularity into the 
system. The following description of the Japanese system 
may serve by way of illustration. 

We have a Japanese field before us, in the middle of October, 
with nothing but buckwheat upon it. The buckwheat is planted 
in rows, 24 to 26 inches apart ; the intervening, now vacant, 
space had been sown in spring with small white turnip- 
radishes, which have already been gathered. These intervening 
vacant spaces are now tilled with the hoe to the greatest depth 
attainable by the implement. A portion of the fresh earth is 
raked from the middle up to the buckwheat, which is now in 
full flower : a furrow is thus formed in the middle, in which 
rape is sown, or the grey winter pea, the seed being manured in 
the manner already described, and seed and manure afterwards 
covered with a layer of earth. By the time the rape or the 
peas have grown one to two inches high, the buckwheat is ripe 
for cutting. A few days after the rows in which it stood are 
dug up, cleared, and sown with wheat or winter turnips. Thus 
crop follows crop the whole year through. The nature of the 
preceding crop is a matter of indifference, the selection of the 
succeeding one being determined by the store of manure, the 
season, and the requirements of the farm. If there is a defi- 
ciency of manure, the intervening rows are allowed to lie fallow, 
until a sufficient quantity has been collected for them. 

This system, as a whole, has also this great advantage, that 
the manure may be used at all times, and need never lie idle 
as a dead capital bearing no interest ; and moreover, perhaps, 
the most important point of all is that a direct ratio is thereby 
secured between the power of the soil, as shown in the crops. 



JAPAIiTESE HUSBANDRY. 401 

and the stock of manure on hand, a ratio not disturbed here by- 
artificial means or by any ' tour de force.^ Expressed in other 
words, the income and expenditure of the soil are always kept 
evenly balanced. 

I have seen this system carried out to the fullest attainable 
degree in the vicinity of large towns, such as Jeddo, also in 
particularly fertile valleys, and on fields bordering on the great 
highways. Here crop succeeded crop, manure followed manure. 
Here the plot of ground produced much more than could be 
consumed on it ; but the great city and the privies on the high- 
road returned a supply of manure to balance the export of 
produce. 

I have, however, also had occasion to visit farms situated on 
some hilly part far away from the high road, and only recently 
reclaimed and cultivated. As the Japanese farmer, as a general 
rule, prefers the valleys to the hilly ground, the supply of manure 
here is more restricted and more difficult, and any addition to it 
from towns or by travellers is almost altogether out of the ques- 
tion. Here I found occasionally only one crop on the ground ; yet 
the rows were so wide asunder that another crop would have 
found ample space between them. With this system it is at 
least possible to till properly and repeatedly the intervening 
spaces, which are intended to receive the next crop ; besides 
the constant supply of fresh earth to the present crop, by raking, 
places a larger store of soil at the disposal of the latter than 
could be done in any other way. In this manner only the one- 
half of the field (corresponding to the limited supply of manure) 
is actually made to produce ; but the system of planting the 
crop in drills wide asunder always gives a much more abundant 
return than could possibly be obtained, if the one-half of the 
field as a continuous plot were completely sown, the other half 
being allowed to lie fallow. As the home production of manure 
or the importation of it from other parts, increases, the farmer 
proceeds to fill part also of the vacant rows, which thus leaves 
only the third or fourth part of the field fallow, until, at last, 
every row is made to produce crops. 

How wide the difference between this system and ours! 
When we break up and till a plot of ground, we begin by 
extracting from it three or four harvests, without bestowing a 

D D 



402 APPENDIX II. 

particle of manure, and apply manure only when the soil is 
exhausted. The Japanese husbandman never breaks up a plot 
of land, unless he possesses a small stock of manure, which he 
may invest in the ground ; and even then he only cultivates this 
new plot to the extent his supply of manure will permit. This 
rational proceeding shows the deepest insight into the nature of 
the system of agriculture to be pursued with a reasonable pros- 
pect of securing a constant succession of remunerative crops. 
No other illustration can so clearly show the difference between 
our European way of viewing the matter and the Japanese. 
We, in Europe, cut down the trees on a forest plot, sell the 
timber, grub up, plough and till the ground, and then proceed 
to dispose of the productive power of the new soil, in three 
cereal crops, obtained without the least supply of manure ; or 
we may possibly assist in accelerating the exhaustion of the 
ground by a small dose of guano. All that this course of pro- 
ceeding is calculated to accomplish is, that we have now to 
distribute the manure hitherto produced on our estate over a 
somewhat more extended surface than formerly. When the 
Japanese husbandman breaks up a plot of ground, he finds a 
virgin soil, the productive power of which he has not the least 
intention of impairing. He therefore, from the very outset, 
takes care to establish a proper balance between crop and 
manure, expenditure aud income, maintaining thus intact the 
productive power of the ground, which is all that can reasonably 
be attempted by any rational husbandman (' Annal. der 
Preuss. Landwirthschaft,' January, 1862). 



APPENDIX H (page 247). 

We would earnestly recommend all inquiring travellers^ in 
other parts of the world, to endeavour to ascertain, above all 
things, what are the proportions of the annual produce of the 
various cereals and cultivated plants raised in a continued suc- 
cession of crops on unmanured soil of different kinds in the 
same place, and under the climatic influences of widely differing 
degrees of latitude. In so far as tlie author has been able to 



MINERAL MATTERS SUPPLIED BY IRRIGATION. 403 

obtain reliable information on the matter, from various countries, 
more especially from the torrid zone, a careful examination of 
the facts ascertained woiild appear to refute everywhere the old 
wide-spread error that a very fruitful soil, under favourable 
climatic conditions, in the tropics for instance, will continue in- 
exhaustible, even without receiving back from the hand of man 
the mineral matters removed in the crops. Even in the most 
enchanting lands of the tropical zone, on the most fruitful vol- 
canic earth, such as is found in the old country of the Incas, 
the tableland of Quito, Imbabura, Eiobamba, Cuenca, &c., a 
long-continued succession of crops drained the soil wherever it 
was impracticable to convey to the fields by artificial irrigation 
the mud carried down by the torrents of the Andes. In those 
regions water, aided by the wide-spread old volcanic mud 
streams (Lodozales), plays the part, which guano and farm-yard 
manure do elsewhere, of restoring to the soil the mineral con- 
stituents removed by a continued succession of crops. In most 
of the provinces of Persia, more especially in Aserbeidschan and 
in a great portion of Armenia and Asia Minor, the' irrigation 
canals everywhere met with serve the purpose, not so much of 
moistening the ground, as of conveying to the land in the 
valleys the mineral detritus washed from the mountains at the 
time of the melting of the snow. This method of artificial 
manuring by irrigation is commonly applied also in those 
countries where there is no lack of rain and dew. It subserves 
the same purpose as the mud of the Nile in Egypt, viz. to 
replace the action of farm-yard manure. Where the mineral 
constituents removed by a long succession of crops are not 
restored to the ground either by animal manure, or by irrigation, 
the soil is almost completely drained of its productive powers, 
as is the case, for instance, in certain parts of the extensive 
table-lands of Tacunga and Ambato (in the South-American 
State Ecuador), where barley will often barely give a two or 
threefold return, notwithstanding the frequent alternations of 
rain and sunshine. From the most reliable information ob- 
tained by me, even the most fertile estates in San Salvador and 
Chiriqui, in Central America, with their most fruitful, loose, tra- 
chytic soil, abounding in potash and silica, cannot show a single 
field on which maize has been grown for thirty years running 

D D 2 



404 APPENDIX H. 

without a considerable reduction of produce — a fact whicli 
sufficiently refutes the old mistaken notion of the inexhaustible 
fertility of the soil in the tropics. 

On the western coast of Peru only those parts are extremely 
sterile, where no little artificial canals convey to the dry soil the 
water from the torrents of the Andes, which carries with it the 
mineral detritus washed from the declivities of the mountains. 
Wherever such artificial canals exist, and the conditions of the 
ground are favourable, the soil on the coast as well as in the 
interior of Peru and Bolivia is almost as productive as in the 
interior of the highlands of Ecuador, New Grranada, and Guate- 
mala. But it is not the water which is the agent in maintaining 
the steady productiveness of the soil, but, as in the case of 
the Delta of the Nile in Egypt, it is the mud carried along 
with the water, and which has been washed away from the dis- 
integrated rocks of the Andes. The constituents of this mineral 
detritus, which are partly contained in the water in a state of 
minute mechanical division, and partly held in chemical solu- 
tion, are brought to the fields by small channels. The water 
thus conveyed from the mountains in innumerable furrows is 
soon absorbed by the soil or evaporated, leaving a rich fertilising 
deposit behind. Pure rain water would be of very little avail, 
as, for instance, in the extensive tableland of Tacungar, with its 
barren pumice stone fields, where quite near the equator rain 
pours down almost daily during nine months of the year. It is 
not the atmospheric water that acts as the fertilising agent, but 
the muddy streamlets from the Andes. In Peru the fertilising 
action of guano is more enduring than in England, because the 
potash which the guano does not restore to the soil, is there 
supplied in the detritus from the trachytic constituents of the 
Andes ridge, which abound in felspar. This natural mineral 
manure is of the same high value in the South American lands 
of the Andes chain as the fertile Loss, accumulated by the great 
flood in past ages at the foot of the Bavarian and Swiss Alps. 
It is a fact full of meaning that the inhabitants of those parts 
of America should have arrived at the same simple means of 
restoring to the land the mineral constituents carried away by 
the crops, which are at the present day generally resorted to 
also under similar favourable conditions of the ground in the 



ANALYSIS OP CLOVER. 



405 



mountainous regions of Asia Minor, Armenia, Grrusia, Western 
Persia, as well as in the north of Mesopotamia (Mossul), and, if 
I mistake not, in Thibet also. The waters of the rivers Kur, 
Araxes, Euphrates and Tigris, are in spring just as turbid and 
as much impregnated with mud, which simply means earthy- 
particles, as the Nile, and as the East Persian river Herirud, 
which it is well known is altogether absorbed up in fields and 
gardens. The experience of ages past has no doubt taught the 
inhabitants of these ancient countries, in both hemispheres, this 
way of restoring to their fields the incombustible constituents 
removed from them in the produce carried away to the large 
towns (Professor Dr. Moritz Wagner ; see Supplement to ' Augsb. 
Allg. Zeitung,' No. 36, February 5, and No. 173, June 22, 
1862). 



APPENDIX I (page 341). 

ANALYSIS OF CLOVEK MADE BY DE. PINCUS. 

100 parts of air-dried clover contained, — 





Unmanured 


Manured with 


Manured with 




sulphate of magnesia 


sulphate of lime 




s 


> 

o3 


t; 


1 


B 


s 

5 


u 
% 


'-+J 


a 


i 


S 

% 


"S 

P. 


























Water .... 


CO 


k1 


f^ 


W 


m 


vA 


(^ 


H 


£B 


i-:i 


s 


H 


12-25 


13-04 


15-05 


12-95 


13-00 


14-45 


12-12 


13-27 


11-85 


10-70 


12-24 


11-60 


Vegetable fibre . 


39-55 


15-07 


16-36 


28-85 


39-47 


12-58 


17-08 


29-70 


38-75 


13-73 


16-96 


29-87 


Mineral constituents . 


5-05 


11-16 


6-32 


6-95 


6-76 


10-97 


7-47 


7-94 


6-65 


11-46 


7-45 


7-96 


Protein substances 


10-15 


22-08 


17-59 


14-70 


11-42 


24-37 


19-59 


15-81 


12-34 


28-74 


20-57 


17-45 


Hydrate of carbon 


33-00 


38-65 


44-68 


36-55 


29-36 


37-63 


43-74 


33-28 


30-41 


35-38 


42-78 


33-12 


100-00 


100-00 


100-00 


100-00 


100-00 


100-00 


100-00 


100-00 


100-00 


100-00 


100-00 


100-00 


Total quantity of nutri- 


























tive substances 


43-15 


60-73 


62-27 


51-25 


40-78 


62-00 


63-33 


49-09 


42-75 


64-12 


63-35 


50-57 


Proportion of the pro- 


























tein substance to the 


























hydrate of carbon . 


1:3-25 


1:1-75 


1:2-54 


1:2-46 


1:2-57 


1:1-54 


1:2-23 


1:2-10 


1:2-46 


1:1-23 


1:2-08 


1:1-90 



406 



APPENDIX I. 



Ash Constituents. 
100 parts of ash contained, — 





Clover 
unmanured 


Clover maniured 


Clover manured 


Chlorine 


witli sulphate 
of magnesia 


with sulphate 
of lime 


1-93 


1-22 


1-73 


Carbonic acid 










21-43 


21-75 


19-17 


Sulphuric acid 










1-33 


2-36 


3-29 


Phosphoric acid 










7-97 


8-49 


8-87 


Silicic acid . 










2-67 


2-55 


3-08 


Potash 










33-58 


32-91 


35-37 


Soda . 










2-12 


3-03 


2-73 


Lime . 










21-71 


20-66 


19-17 


Magnesia 










5-87 


5-27 


5-47 


Sesquioxide of iron 








0-94 


1-22 


0-94 












99-55 


99-46 


99-82 



Calculated upok the Ash eeee from Carbonic Acid. 





Clover 


Clover manured 


Clover manured 




with sulphate 


with sulphate 


Chlorine 




of magnesia 


of lime 


2-46 


1-56 


2-14 


Sulphuric acid 










1-69 


3-02 


4-07 


Phosphoric acid 










10-14 


10-85 


10-97 


Silicic acid . 










3-40 


3-26 


3-81 


Potash 










42-73 


42-05 


43-77 


Soda . 










2-70 


3-87 


3-37 


Lime . 










27-62 


26-40 


23-72 


Magnesia . 










7-47 


6-74 


6-77 


Sesquioxide of iron 








1-20 


1-56 


1-16 












99-41 


99-31 


99-78 



The remarkable investigations by Dr. Grrouven of the Glover 
disease deserve also a place here. 

The so-called * clover disease ' manifests itself in the clover 
plant, at the period of flowering, by the appearance of a multi- 
tude of brown spots of cryptogamic plants covering stems and 
leaves. The result of the affection is not simply a failure of 
the clover crop, but the produce reaped is unwholesome for 
cattle. 

In his examination of the diseased clover, Grouven compared 
the organic and the ash constituents of the diseased with those 



CLOVEE DISEASE. 



407 



of the healthy plant. Both the healthy and the diseased clover 
were produced from a mixture of seeds of red clover, lucerne, 
and esparsette, such as is usually grown at Salzmunde, where 
the experiments were made. The samples for examination and 
analysis were taken from the field on August 12. The analysis 
of the healthy plant was confined to the determination of the 
organic substances and the amount of ash. 

100 parts of air-dried clover-hay contained, — 



Water 

Protein substances 

Fat 

Saccharine matter, calculated as starch* . 

Non-azotised compounds unknown 

Woody fibre ....... 

Ash ........ . 


Diseased clover 


Healthy clover 


16-2 

16-7 

3-6 

7-0 

17-9 

31-7 

6-9 


16-2 
11-7 

2-8 
18-5 
11-3 
31 -41 

8-1 


100-0 


100-0 



The composition of the ash of the diseased clover was com- 
pared with that of the ash of red clover (Wolff) and esparsette 
(Way).t The ashes were calculated after deduction of carbonic . 
acid, sand, clay, and sesquioxide of iron. 





Diseased clover 


Bed clover 


Esparsette 


Potash 


(GrROUVEN) 


(Wolff) 


(Way) 


3-32 


35-0 


35-8 


Soda . 








0-87 


0-7 


3-5 


Lime . 








55-71 


32-8 


35-9 


Magnesia 








13-08 


8-4 


0-5 


Chlorine 








2-76 


3-5 


2-0 


Sulphuric acid 








13-46 


3-3 


2-8 


Phosphoric acid . 








5-99 


8-4 


9-6 


Silicic acid . 








4-88 


7-0 


4-3 










200-07 


99-6 


99-4 



Grrouven is led to conclude from the result of his examination 



* Substances convertible into sugar by sulphiu'ic acid, 
t With 0-1 of ash and 0-184 of protein substances. 
:j; Compare also the preceding analysis by Dr. Pincus. 



408 APPENDIX I. 

that the primary cause of the clover disease is attributable to a 
change in the chemical composition of the plant, which again is 
caused by an altered condition of the soil. The very consider- 
able deficiency of phosphoric acid and potash in the ash of the 
diseased plant is certainly remarkable (' Zeitschrift der land- 
wirthschaftlichen Centralvereins der Provinz Sachsen, 1861,' 
page 73). 



INDEX. 



ABS 

ABSOEPTION, power of, in soils, for 
food of plants, 65 
in charcoal, for colouring mat- 

tpr and gases is a surface attraction, 65 
in soils, is accompanied by 

chemical decomposition, 69 
for compounds of soda, and 

for silicic acid, 80, 135 

varies in each soil, 134 

for potash, 134 

for silicic acid and ammonia, 

135 
• — is inversely as the diffusibility 

of food, 134 
shows the depth to which food 

penetrates, 223 

— — — in turf, 107 

— by roots of plants not osmotic, 51 

— • value of knowledge of to 

agriculturists, 225 

— of nutriment by roots of plants, 86 

— of silicic acid, influence of organic 
matter on the, 80 

— . number of soils, meaning of, 136 

— — — — for ammonia, potash, 
phosphate of lime, and phosphate of 
magnesia and ammonia, 136 

— — — — importance of, to agri- 
culturists, 138 

Agriculture, progress of, impossible if 
dependent on a supply of ammonia, 
322 

— in Europe still young, 243 
Agricidtural produce, the permanence 

of, regulated by a law of nature, 243 
Agrostemma cithago, ash of, 235 
Ahrend's examination of the oat plant 

at different stages of growth, 35 
Aloe, food of, stored in leaves, 26 
Alumina in club-moss, 60 
Ammonia, absorbed by different soils, 

135 

— absorption, number of, 136 

— absorbed strongly in soils, rich in 
humus, 141 



APP 
Ammonia, action of the salts of, by 
themselves and in guano, 258, 296, 303 

— action of salts of, on earthy phos- 
phates, silicates, &c., 79 

— amount of in rain and dew, 289 

— always present in air, 290 

— calculation of amount of, that would 
be required in Europe, 323 

— compounds of, by themselves not im- 
portant, 319 

— cost of, precludes its extensive use, 
325 

— comportment of, with arable soil, 135 

— diffusibihty in soils, 79 

— in drain water, 91 

• — • in lysimeter waters, 92 

— in spring and river water, 96 

— salts of, as food and as means of dis- 
tributing food in soils, 131, 335 

— in farm- yard manure and soils not 
separable by distillation with alkalies, 
312, 315 

— in manures compared with corn pro- 
duced, according to Lawes, 322 

— manufactured too limited in quan- 
tity to be trusted to, 323 

— use of, limited by its price, 325 

— nitrite of, formed by oxidation, 326 

— loss of, in lime soils, by oxidation, 
330 

— theory, 296, 309 

Ammoniacal compounds, experiments 
with, by Schattenmann, 297 

by Lawes and Gilbert, 298 

by Kuhlmann, 336, 304 

— — and with guano, by the 

Bavarian Agricidtural Society,301,336 

Anderson on the growth of turnips, 18 
Annual plant, growth of, 13, 28, 32 
Anthemis arvensis, ash, analysis of, 235 
Appendix A, analysis of birch leaves, 
353 

— B, on the starch in the stems of 
palms, 356 

— C, Hale's vegetable statics, 357 



410 



INDEX. 



APP 

Appendix D, analysis of drainage, lysi- 
meter, river, and marsh waters, 363 

— E, growth of plants in solutions of 
their food, 272 

— F, on the growth of beans in pow- 
dered turf, 385 

— Gr, on Japanese husbandry, 386 

— H, on mineral matters supplied by 
ii-rigation, 402 

— I, analysis of clover, 407 

Aqiiatic plants from Ohe and Iser, 
analysis of ash of, 370 

Arable soil, absorptive power of, 67, 69, 
134 

abounds in nitrogen, 306, 311 

chemical decomposition produced 

by, 69 

formation of, 68 

food present in, in state of phy- 
sical combination, 71 

food present in, in state of chemi- 
cal combination, 72, 74 

mode of estimating nutritive mat- 
ter in, by chemical analysis, 119 

Ash constituents, number necessary for 
the growth of plants, 2 

necessary for the formation of 

organic compounds, 24 

Asparagus, analysis of the ash of, 358 

Average crop, meaning of, 252 

of wheat, rye, and oats, 167 

— ■ — diminution of, in Hessian Rhine, 
253 

BADEN, Grand Duchy of, food of sol- 
diers in, 272 
Baker and Jarvis islands, guano, 278 
Barley, action of soda in the production 
of seed in, 339 

— plant, mode of growth of, 154 
Bavarian experiments with salts of am- 
monia and guano, 301 

with sea salt, 336 

with nitrates, 339 

— — with superphosphates, 147 
Beans, growth of, in powdered turf, 109, 

385 
Beech leaves, analysis of, 353 
Black soil, of Eussia, its fertility, 221 
Bieianial plants, growth of, 17 
Bineau, amount of nitric acid and ammo- 
nia in rain water, estimated by, 289 
Bogenhausen, experiments with sea salt, 
337 

with salts of ammonia and with 

guano, 302 
■ — soil, amount of nitrogen in, 305 
Bones acted on by steam, 277 
Bone-earth, distribution of in the soil 
effected by organic matter, 77 



CLO 

Bone-earth and guano compared as to 
rapidity and duration of action, 279 

Saxon experiments with, 279 

with salts of ammonia, effects of 

compared with guano, 258 

Bottger, formation of nitrite of ammonia 
by, 327 

Boussingault, amount of ammonia in air, 
290 

and nitric acid in rain 

water and dew, 290 

formed in com- . 

bustiou of coal gas, 327 

— on the growth of plants without ni- 
trogenous food, 43 



pENTAUEEA, Cyanus, ash of, 235 

Cereals, meaning of average crop of, 
252 

— average crops of in Bavaria, 211 

in Hessian Ehine, 253 

• — conditions for their gi-owth, 142 

— change produced in the arable soil 
by the crdtivation of, 226 

— cause of difference in corn and straw 
in, 198 

— effect of removing leaves, &c. from, 
before flowering, 28 

— nitrogenous compounds in, not al- 
ways the same, 257 

— influence of lime or magnesia on 
the nitrogenous compounds in, 258 

— influence of temperatiu?e on the 
growth of, 34 

— ratio between albuminous and non- 
albuminous constituents in seeds of, 
40 

— increase at first in roots, 34 

— produce of stalks and shoots in pro- 
portion to the developement of roots, 
34 

— produce of, with superphosphates, 
147, 150 

— compounds of ammonia, 

296, 302, 303, 304 
common salt and nitrate 

of soda, 336 
Charlemagne, records of, 243 
Chemical analysis of soils, limited value 

of, 221 
Clover, analysis of, 405 

— ash, analysis of, 406 

— diseased, analysis of, 407 
ash, analysis of, 407 

— effect of gj'psum on, 341 

— crops bear no proportion to the sul- 
phm-ic acid in the experiments of Dr. 
JPineus, 344 



INDEX. 



411 



CLO 

Clover, requires nearly the same consti- 
tuents as the potato, 207 

— and turnips, e£fect of in opening 
the soil, 90 

-T- sick field, 137 

explanation of by Lawes and 

Gilbert, 162 

Compensation, law of, 242 

Compost, 145 

Compound manures, action of, not de- 
pendent upon one constituent alone, 
263 

Copper in ash of plants, 58 

Corn, conditions for formation of, 199 

Corn and straw, constituents in soils, 
200 

relative proportions of in 

cereals affected by the weather, 192 

— in the Saxon ex- 
periments, 198, 203 

Crops reaped afford no indication of 
quantity of nutritive matter in the 
ground, 194 

Cunnersdorf, manure experiments, 190 

— produce of unmantu'ed fields of, 190 

— nearness of food in soil of, 197, 204 

— produce with farm-yard manure, 208 

— increased produce by farm-yard 
manure, 209 

— soil, depth to which manure pene- 
trates, 224 

— produce with guano compared with 
farm-yard manure, 267 

— produce with bone-earth and com- 
parison with guano, 279 

— prodiice with rape cake, 283 

— experiments, effect of the nitrogen 
in, 285 



DECREASING crops, progress of, 
169 
Diffusion, law of, does not explain the 
absorption of food by roots of plants, 
53 

— experiments, 56 

Disinfection of excrements does not 

affect their energy, 274 
Distribution of food by chemical and 

mechanical means, 87 
Drainage, effect of, 90, 95 

— removal of siliceous plants by, 81, 

— water, its composition, 91 

— — anaysis of, 363 

does not dissolve the food of 

plants, 95, 96, 102 
Duckweed, power of selection in roots 

of, 51 
Dung, mechanical action of, 145 



FAR 

EARTHY phosphates, 276 
effect of, less marked in first 

year, 278 

— — diffusion of, through the soil, how 
effected, 75, 77, 137 

— ■ — • require the presence of potash 
and silicic acid in the soil, 278 

— — and guano, comparative experi- 
ments with, 279 

European husbandry, present state of, 
237 

decline of, produced by the sys- 
tem of farm-yard manuring, 252 

illustrated by Hessian 

Rhine district, 253 

Excrement, contain ash of food, 184 

— of man, 272 

collection of, in Rastadt, 273 

value of, 273 

not injm'ed by disinfecting 

with sulphate of iron, 274 
Exhaustion of soils, its nature, 74, 76, 

212 
— known by the average crop, 

252 
in chemical and agricultural 

sense, 166 

law of, 167 

• — ■ retarded by growth of fodder 

plants, 175 

— of wheat, oat, and rye soils, 172, 
177 



FALLOW, 74 
False teachers in agriculture, 239, 
247 

Farm-yard manure, 144 

— • effect of, varies with the 

composition of the soil, 212 

depends on the mi- 
nimum nutritive matters in the soil, 
213 

its mechanical action, 214 

restores fertility only by sup- 
plying one or more deficient ingre- 
dients of the soil, 213; 229 

law regulating the quantity 

to be applied, 218 

produce from, 208 

— — in the Saxon experi- 
ments not always equal to the quan- 
tity ^applied, 209 

why generally useful, 214 

Saxon experiments with, 208, 

218 

— — manuring system, 188, 226, 
236 



412 



INDEX. 



FAR 



LEA 



Farm-yard mamiring system, changes 
produced in the composition of the 
soil by, 226 

. final result of, 231 

illustrated in 

the Saxon experiments, 231 

Fodder plants, proportion retained in 
bodies of animals, 227 

transfer food from subsoil to 

surface soil, 26 

Fontinalis, antipyxetica, ash analysis of, 
370 

Food, physically and chemically com- 
bined in soils, 71 

— not absorbed by plants from solu- 
tions in soils, 85, 95, 102 

— diffusion of, in soils, how eifected, 
75, 77 

by chemical and mechanical 

means, 87 

— closeness of in soils, 197 

GROUVEN, analysis of diseased 
clover, 407 
Guano, amount of, equivalent to farm- 
yard manure, 301 
• — and bone-earth, effects of, compared, 
279 

— and farm-yard manure, amount of 
phosphates and nitrogen in, 264 

— from Baker and Jarvis islands, 278 

— fertilising action of, attributed to 
its nitrogen or ammonia, 258, 296 

due in many cases to fixed 

constituents, 258 

— deficient in potash, 261 

— and farm-yard manure, effects of, 
compared, 261 

— when its application will be success- 
ful, 263 

— continued use of, exhausts the soil 
of sUica and potash, 264 

— mixed with sulphuric acid and turf 
or sawdust, 265 

— peculiar effects of, illustrated in the 
Saxon experiments with different 
crops, 265 

— and salts of ammonia, comparative 
experiments with, in Bavaria, 301 

Gypsum, 335 

' — experiments on clover, 340 

— action of arable soil on solutions of, 345 

— effects the distribution of potash 
and magnesia in soUs, 347 



HORSE-CHESTNUT, analysis of ash 
of leaves of, 356 
Human excrements, value of, as maniu'e, 
illustrated at Rastadt, 272 



Human excrements, price of, 272 

not injured by deodorising by 

sulphate of iron, 274 



IGNORANT practical men, 249 
Iodine, different amount in different 
plants, 58 
Iron necessary for plants, 57 
Irrigation, mineral matters supplied in, 

402 
— water, suspended mud of, most va- 
luable, 403 



JAPANESE husbandry, 387 
dispenses with cattle feeding, 

389 

— soil, 386 

— supply of manure, 390 

— mode of constructing privies, 391 

— mode of preparing excrements and 
compost for application in field, 392 

— system of manuring, only one of 
top-dressing, 393 

— system of planting in rows, 394, 
399 

— husbandry compared ■with European, 
396 

— tillage of the soil, 398 

— succession of plants illustrated, 400 
Jerusalem artichokes, effect of the cul- 
tivation of, on arable soil, 222 



KNOP, experiments of, on growth of 
plants in solutions of their food, 373 
Kolbe, formation of nitrous acid, 327 
Kotitz, unmanured field produce from, 

190 
Kroker, estimation of nitrogen in soils, 

306 
— analysis of drainage water, 364 
Kuhlmann, experiments with salts of 

ammonia, 304, 336 

sea salt, 336 

Lirae, 350 



LARGE crops indicate the available 
condition of the mineral food, 194 

depend on the closeness of the 

nutritive substances in the soil (fi- 
gxu'e), 195 

Lawes and Gilbert on clover sickness, 
157 

reason of the failure of the ex- 
periments of, 160 

Leaves, principal conditions for the for- 
mation of, 234 



INDEX. 



413 



LEA 



NUT 



Leaves, removal of, from turnips, 27 
Lime alters the condition of the soil, 
349 

— beneficial effect of, 83 

— experiments with, 350 

— action of, on soils, 81 

on a drained marshy soil, 84 

— water, effect of arable soils on, 351 
Lysimeter waters, 92 

analysis of, 363 



MAGNESIA, dispersed in soils by the 
agency of gypsum, 347 

— influence of, on the formation of 
nitrogenous compounds in seeds, 258 

— necessary to plants, 257 

Maize, growth of, in solutions of its 
food, 375 

— in flower, produces seeds if placed 
in water, 38 

Manure, nature of, 183 

— and tillage, 131 

— change in the classification of, 308 
Manure, beneficial action of, in restoring 

the relative proportions of mineral 
matters in soils, 127 

— excessive use of, gives no advantage, 
213 

— reason of decreasing value of, by 
system of rotation, 230 

— nitrogen, classification of, 294 

— action of, not always proportional to 
quantity used, 215 

Manured land, produce of, in Saxon 

experiments, 208 
Marine plants, power of selection of 

food in roots of, 52 
Matricaria chamomilla, ash of, 235 
Maiisegast, unmanured field, produce 

from, 190 
Mayer, experiments on soils with 

caustic alkalies, 312 
Meadow grass, effect of sea-salt on, 

340 
Metals found in plants, 55, 57 
Mineral matters, absorption of, by soils, 

133 
to be restored, vary in different 

soils, 250 

— ■ — restored by farm-yard manure, 
227 

lost in crops in the Saxon ex- 
periments, 232 

restoration of all, necessary, 249 

Minimum, law of, 213, 216 

Monocarpous plants, have distinct pe- 
riods of growth, 25 

Moss water, analysis of, 372 



NAEGELI, experiments on nutrition 
of plants, 106 

Nile, valley of, reason of its permanent 
fertility, 246 

Nitrate of ammonia, formation of, 327 

Nitrate of soda, 334 

action of, on earthy phos- 
phates, 79 

— experiments on cereals with, 

by Bavarian Society, 338 

Nitric acid in rain water, 289 

Nitrogen classification of mamu'es, 294 

— esteemed chief agent in manures, 
293 

— indefinite idea of, in manures, 294 

— assimilable and sparingly assimi- 
lable, 295 

— amount of in soils, 305 

— amount of, in different layers of 
soils illustrated in Russian black soil 
and in Caen soil, 311 

— cause of the inactivity of the great 
mass of, in soils, 319 

— most abundant in the upper ten 
inches of soils, 311 

— in soils and farm-yard manure com- 
pared as to effect, 315 

— profit and loss of, in the Saxon ex- 
periments, 291 

Nitrogen compounds, function of, iu 

seeds, 45 
in annuals, 45 

— — in perennials, 47 

in soils bear no ratio to their 

productive powers, 306 
supposed different forms of, in 

soils as operative and inoperative, 

307, 309 

— — in soils not distinguished by ac- 
tion of alkalies, 312 

in farm-yard maniu'e only partly 

separable by distillation with alkalies, 

315 
in manures and soils, different 

effects of, on what dependent, 316 
Nitrogenous food, experiments on the 

growth of plants without, 43 
removed in crops is more than 

fully restored by rain, 292 
restored to soils by fodder plants, 

329 
Nitrogenous manures not always the 

most efficacious, 286 
effects of, not proportional to the 

nitrogen present, 303 

first effect of, 331 

when required, 329 

Nutritive substances, closeness of in 

soils (figure), 195 



414 



INDEX. 



NUT 



RYE 



Nutritive substances, proper relative 

proportions of, 127 
maximum and minimum of, in 

soils, 213 
minimum of, regulate tlie crop, 

213 
effect of the absorption of, in the 

upper layers of the soil, 151 

OAT, food of, derived from arable soil 
(figure), 204 

— and tm'nip compared, 39 

— several stages of growth of, 35 
Oberbobritzsch, unmanured field, pro- 
duce from, 190 

Oberschona, unmanured field, produce 
from. 190 

Organic matter in manure does not ar- 
rest exhaustion, 185 

incorporation of in soils improves 

their physical condition, 89 

Osmosis, laws of, 53 



"pALMS, starch in stems of, 356 

Peas and barley plant, growth of com- 
pared, 154 

Perennial plant, mode of growth of, 13 

Peruvian guano, composition of, 256 

and ash constituents of seeds, 

difference of, 257 

. effect of, due to the presence of 

oxalic acid, 259 

moistened with sulphuric acid 

made more quickly available, 260 

Phosphate of lime, diffusion of in soil, 

79 

Phosphoric acid and nitrogen, propor- 
tion between in oats and turnips, 39 

Pierre, analysis of soil by, 311 

Pineus, experiments on clover with gyp- 
sum, 340 

Plants, annual, biennial, and perennial, 
vital properties compared, 13 

— annual, mode of growth of, 17 

. leafy, mode of growth of, 28 

— biennial, mode of growth of, 18 

— perennial, mode of growth of, 14, 26 
growth of, without nitrogeneous 

food, 43 

— growth of in turf, 106 
in solutions of their food, 103 

— imderground organs of, 12, 14 

— rich in starch, sugar, and gum, con- 
tain much potash in their ash, 24 

store up food in certain organs for 

future use, 26 
Pools, analysis of stagnant water of, 96 



Potash in soils, not always available, 
248 

— necessary for vegetation, 257 
Potato, constituents of, 204 

— draws its principal constituents from 
the arable surface soil, 204 

— effect of the cultivation of, on arable 
soil, 222 

Poudrette, nature of, 271 

Practical men, 246 

their teaching and practice often 

opposed to each other, 333 

Protoplastem of wheat plants, propor- 
tion between nitrogenous and non- 
nitrogenous substances in, 41 



■pADICATION of plants, 9 
AX importance of a know- 
ledge of, 11 
Pape-cake, its composition, 282 
more diffusible in soils than 

guano, 283 
its fertilising action illustrated in 

the Saxon experiments, 283 
Eastadt, soldiers' food and excrements, 

272 
Restoration, law of, properly interpreted, 

251 
Rhenish Bavaria, exhaustion of soil of, 

245 
River waters, analyses of, 371 
Roots, absorption of mineral matters by, 

59, 80 

— absorption of food by, not an osmotic 
process, 53 

— do not offer permanent resistance to 
the chemical action of salts, 56 

— importance of their developement in 
cereals, 34 

— mode in which they absorb food, 
100 

— length of, 11 

• — power of selection of food in, 51, 
55 

— principal conditions for the formation 
of, 234 

— spread in search of food, 85 
Rotation, succession of crops in, ^ de- 
pendent on the cereals, 235 

— system of, does not ultimately in- 
crease corn crops, 241 

— general results obtained in the Saxon 
experiments by, 285 

Rye, cultivation of, instead of wheat, 
shows deterioration of soil, 245 

— soil, 115 

— — conversion of, into wheat soil, 
123 



INDEX. 



415 



SAN 
HANDY soil, productive power of, 139 

O and loam compared, 140 

Sap, Hales' experiments on the motion 

of, 359 
Saxon experiments witli lime, 350 

on unmanured land, 190 

with farm-yard manure, 208, 218 

with bone-earth, 279 

with rape-cake, 283 

profit and loss of nitrogen in the 

soil, 291 
Schattenmann's experiments with salts 

of ammonia, 297 
Schmid, on nitrogen in Russian black 

soil, 311 
Sehonbein, nitrite of ammonia in 

oxidation and combustion discovered 

by, 326 
Sea-salt, experiments with, by Kuhl- 

mann, 336 
with cereals, experiments by Ba- 
varian society, 336 
Seeds, germination and growth of, 3 

— conditions for the formation of, 49 

— effect of mineral matter on the growth 
of, 44 

— functions of nitrogenous matter of, 
43 

— importance of good, 7 
- — selection of, 8 

Silicates, effect of organic matter in 

soils, in the diffusion of, 80 
Siliceous plants, removed by drainage, 

81 
Silicic acid, deficiency or excess in soils 

injurious, 81 

excess of, how remedied, 82 

distribution of, promoted by 

growth of grass, 80 
Soil and subsoil, 64 

— when fertile, 65 

— chemical analysis of, no guide to its 
productive power, 63, 114 

— exhausted, how restored to fertility, 
73 

— estimation of substances physically 
combined in, 119 

• — for wheat, rye, and oats, 115, 121 

— different layers of, contain food for 
different plants, 154 

— change produced by cereals in, 226 

— composition of, restored by fodder 
plants, 227 

— distillation of, with alkalies, 313 

— from bogs and ditches, fertilising 
effect of, 99 

— exhaustion of, in Ehenish Bavaria, 
245 

— food in, not inexhaustible, 244, 
247 



TOB 

Soil, fertility of, not due to its nitrogen, 
305 

— importance of improving the physical 
condition of, 89 

— mineral matters of, lost in corn and 
cattle sold, 228 

— nutritive power of, estimated by 
amount of food physically combined, 
72 

— productive power of, estimated by 
the available nitrogen in form of am- 
monia and nitric acid, 307 

— progress of exhaustion of, 167 

— production of com and straw in, 
diiring the progress of exhaustion, 
172 

— restoration of productive power to, 
requires nitrogenous as well as mine- 
ral food, 328 

— restoration of niti'ogenous food to, 
effected by fodder plants, 329 

— permeability of, to manures, 223 

— productive power of, 125 

— proper relation between food ele- 
ments in for fertility, 127 

— upper laj^ers of, retain the dung 
constituents, 228 

— saturated with mineral matter, ma- 
nuring with, 143 

— absorptive power of, 67 
effects chemical decompo- 
sition, 69 

knowledge of, valuable, 225 

for potash, 124 

for ammonia increased by 

organic matter, 141 
for phosphates of lime and 

magnesia, 136 

— • — for silicic acid, 138 

Starch in stems of palms, 357 
Stohmann, experiments on the growth 

of plants in solutions of their food, 380 
Straw, formation of, 199, 203 
Subsoil, accumulation of organic matter 

in, injurious to deep-rooting plants, 83 

— period of exhaustion of, 230 

— mineral matter of, supplied to sur- 
face soil by fodder plants, 227 

— not reached by mineral matters of 
manures, 156 

Supei-phosphates, 276 

— experiments with, 147 



rrilLLAGE, beneficial action of, 113 
X Tobacco plant, mode of growth of, 

28 
quantity of albumen and nico- 
tine in, modified by treatmeiat in 
growth, 31 



416 



INDEX. 



TSC 

Tsclierno-sem, or black earth of Russia, 
nitrogen in, 311 

Turf saturated with food of plants, ex- 
periments with, 107 

Turnips, growth of, 18 

influenced by removal of 

leaves, 27 

UNMANUEED land, experiments in 
Saxony on, 190 
produce of, dependent on pre- 
ceding crop, 191 

VOLKEE, absorption of soils for am- 
monia, 140 

— analysis of farm-yard manure, 145 

— estimation of ammonia in farm-yard 
mamrre, 315 

"THTTALNUT leaves, analysis of ash of, 

* f oOO 
Water, drainage, lysimeter, river and 
marsh, analysis of, 96, 363 

— in soils, contains different quantities 
of nutritive matters, 98 

Water, solvent action of, on soils in 

lysimeters, 365 
Way, analysis of drainage water, 363 



ZOE 

Weeds, cause of their production, 234 
Wheat crop, quantity of phosphoric acid 
and potash removed from soil by, as 
compared with rye crop, 119 

— effect of potash on, 339 

— field, retardation of the exhaustion 
of, 175 

— growth of, 33, 41 

— produce of, from salts of ammonia, 
according to Lawes and Gilbert, 322 

— produce of, with superphosphate of 
lime, 147 

— soil, 115 

exhaustion of, 170 

Winter wheat, mode of growth of, 33 

effect of temperature on, 34 

Wood, ash, 287 

mixed with earth for application, 

288 

ZENKER, comparative experiments 
with bone-earth and guano, 279 
Zinc in the ash of Viola calaminaria, 

57 
Zoeller, experiments on the vegetation 
of plants in tiu-f, 106 

— mode of analysing soils, 119 

— analysis of guano by, 257 

— lysimeter waters by, 365 



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